diff --git a/apps/esmtool/record.cpp b/apps/esmtool/record.cpp
index a908a2a45c..a180f87074 100644
--- a/apps/esmtool/record.cpp
+++ b/apps/esmtool/record.cpp
@@ -220,7 +220,7 @@ namespace EsmTool
 {
     void CellState::load(ESM::ESMReader& reader, bool& deleted)
     {
-        mCellState.mId.load(reader);
+        mCellState.mId = reader.getCellId();
         mCellState.load(reader);
         if (mCellState.mHasFogOfWar)
             mFogState.load(reader);
@@ -1358,11 +1358,8 @@ namespace EsmTool
     void Record<CellState>::print()
     {
         std::cout << "  Id:" << std::endl;
-        std::cout << "    Worldspace: " << mData.mCellState.mId.mWorldspace << std::endl;
+        std::cout << "    CellId: " << mData.mCellState.mId << std::endl;
         std::cout << "    Index:" << std::endl;
-        std::cout << "      X: " << mData.mCellState.mId.mIndex.mX << std::endl;
-        std::cout << "      Y: " << mData.mCellState.mId.mIndex.mY << std::endl;
-        std::cout << "    Paged: " << mData.mCellState.mId.mPaged << std::endl;
         std::cout << "  WaterLevel: " << mData.mCellState.mWaterLevel << std::endl;
         std::cout << "  HasFogOfWar: " << mData.mCellState.mHasFogOfWar << std::endl;
         std::cout << "  LastRespawn:" << std::endl;
@@ -1420,8 +1417,7 @@ namespace EsmTool
     std::string Record<CellState>::getId() const
     {
         std::ostringstream stream;
-        stream << mData.mCellState.mId.mWorldspace << " " << mData.mCellState.mId.mIndex.mX << " "
-               << mData.mCellState.mId.mIndex.mY << " " << mData.mCellState.mId.mPaged;
+        stream << mData.mCellState.mId;
         return stream.str();
     }
 
diff --git a/apps/essimporter/converter.cpp b/apps/essimporter/converter.cpp
index 8dcfcfe832..4cf528c832 100644
--- a/apps/essimporter/converter.cpp
+++ b/apps/essimporter/converter.cpp
@@ -204,7 +204,7 @@ namespace ESSImport
         // note if the player is in a nameless exterior cell, we will assign the cellId later based on player position
         if (Misc::StringUtils::ciEqual(cell.mName, mContext->mPlayerCellName))
         {
-            mContext->mPlayer.mCellId = cell.getCellId();
+            mContext->mPlayer.mCellId = cell.mId;
         }
 
         Cell newcell;
@@ -301,8 +301,7 @@ namespace ESSImport
             marker.mWorldX = notepos[0];
             marker.mWorldY = notepos[1];
             marker.mNote = note;
-            marker.mCellId = cell.getCellId();
-            marker.mCell = cell.getCellId().getCellRefId();
+            marker.mCell = cell.mId;
             mMarkers.push_back(marker);
         }
 
@@ -322,8 +321,9 @@ namespace ESSImport
         csta.mHasFogOfWar = 0;
         csta.mLastRespawn.mDay = 0;
         csta.mLastRespawn.mHour = 0;
-        csta.mId = esmcell.getCellId();
-        csta.mId.save(esm);
+        csta.mId = esmcell.mId;
+        csta.mIsInterior = !esmcell.isExterior();
+        esm.writeCellId(csta.mId);
         // TODO csta.mLastRespawn;
         // shouldn't be needed if we respawn on global schedule like in original MW
         csta.mWaterLevel = esmcell.mWater;
diff --git a/apps/essimporter/convertplayer.cpp b/apps/essimporter/convertplayer.cpp
index 5bb9897487..855a473e08 100644
--- a/apps/essimporter/convertplayer.cpp
+++ b/apps/essimporter/convertplayer.cpp
@@ -61,7 +61,6 @@ namespace ESSImport
             const PCDT::PNAM::MarkLocation& mark = pcdt.mPNAM.mMarkLocation;
 
             ESM::CellId cell;
-            cell.mWorldspace = ESM::CellId::sDefaultWorldspace;
             cell.mPaged = true;
 
             cell.mIndex.mX = mark.mCellX;
@@ -74,7 +73,7 @@ namespace ESSImport
                 cell.mPaged = false;
             }
 
-            out.mMarkedCell = cell;
+            out.mMarkedCell = cell.getCellRefId();
             out.mMarkedPosition.pos[0] = mark.mX;
             out.mMarkedPosition.pos[1] = mark.mY;
             out.mMarkedPosition.pos[2] = mark.mZ;
diff --git a/apps/essimporter/importer.cpp b/apps/essimporter/importer.cpp
index 3fac21ec8b..38ebf41596 100644
--- a/apps/essimporter/importer.cpp
+++ b/apps/essimporter/importer.cpp
@@ -409,16 +409,18 @@ namespace ESSImport
         }
 
         writer.startRecord(ESM::REC_PLAY);
-        if (context.mPlayer.mCellId.mPaged)
+        ESM::CellId cellId = ESM::CellId::extractFromRefId(context.mPlayer.mCellId);
+        if (cellId.mPaged)
         {
             // exterior cell -> determine cell coordinates based on position
             int cellX
                 = static_cast<int>(std::floor(context.mPlayer.mObject.mPosition.pos[0] / Constants::CellSizeInUnits));
             int cellY
                 = static_cast<int>(std::floor(context.mPlayer.mObject.mPosition.pos[1] / Constants::CellSizeInUnits));
-            context.mPlayer.mCellId.mIndex.mX = cellX;
-            context.mPlayer.mCellId.mIndex.mY = cellY;
+            cellId.mIndex.mX = cellX;
+            cellId.mIndex.mY = cellY;
         }
+        context.mPlayer.mCellId = cellId.getCellRefId();
         context.mPlayer.save(writer);
         writer.endRecord(ESM::REC_PLAY);
 
diff --git a/apps/essimporter/importercontext.hpp b/apps/essimporter/importercontext.hpp
index e1ecc4074e..9e5d9c0006 100644
--- a/apps/essimporter/importercontext.hpp
+++ b/apps/essimporter/importercontext.hpp
@@ -62,7 +62,7 @@ namespace ESSImport
             ESM::CellId playerCellId;
             playerCellId.mPaged = true;
             playerCellId.mIndex.mX = playerCellId.mIndex.mY = 0;
-            mPlayer.mCellId = playerCellId;
+            mPlayer.mCellId = playerCellId.getCellRefId();
             mPlayer.mLastKnownExteriorPosition[0] = mPlayer.mLastKnownExteriorPosition[1]
                 = mPlayer.mLastKnownExteriorPosition[2] = 0.0f;
             mPlayer.mHasMark = 0;
diff --git a/apps/navmeshtool/worldspacedata.cpp b/apps/navmeshtool/worldspacedata.cpp
index 740e42a099..fd66a46f4c 100644
--- a/apps/navmeshtool/worldspacedata.cpp
+++ b/apps/navmeshtool/worldspacedata.cpp
@@ -263,7 +263,8 @@ namespace NavMeshTool
 
             const osg::Vec2i cellPosition(cell.mData.mX, cell.mData.mY);
             const std::size_t cellObjectsBegin = data.mObjects.size();
-            const auto cellNameLowerCase = Misc::StringUtils::lowerCase(cell.mCellId.mWorldspace);
+            const auto cellNameLowerCase
+                = Misc::StringUtils::lowerCase(cell.isExterior() ? ESM::CellId::sDefaultWorldspace : cell.mName);
             WorldspaceNavMeshInput& navMeshInput = [&]() -> WorldspaceNavMeshInput& {
                 auto it = navMeshInputs.find(cellNameLowerCase);
                 if (it == navMeshInputs.end())
diff --git a/apps/openmw/mwbase/windowmanager.hpp b/apps/openmw/mwbase/windowmanager.hpp
index 0f61939028..198be0fdcf 100644
--- a/apps/openmw/mwbase/windowmanager.hpp
+++ b/apps/openmw/mwbase/windowmanager.hpp
@@ -40,7 +40,6 @@ namespace ESM
 {
     class ESMReader;
     class ESMWriter;
-    struct CellId;
 }
 
 namespace MWMechanics
diff --git a/apps/openmw/mwbase/world.hpp b/apps/openmw/mwbase/world.hpp
index 76b16e4cb0..db8eabe086 100644
--- a/apps/openmw/mwbase/world.hpp
+++ b/apps/openmw/mwbase/world.hpp
@@ -256,10 +256,6 @@ namespace MWBase
             = 0;
         ///< Move to exterior cell.
         ///< @param changeEvent If false, do not trigger cell change flag or detect worldspace changes
-
-        virtual void changeToCell(
-            const ESM::CellId& cellId, const ESM::Position& position, bool adjustPlayerPos, bool changeEvent = true)
-            = 0;
         virtual void changeToCell(
             const ESM::RefId& cellId, const ESM::Position& position, bool adjustPlayerPos, bool changeEvent = true)
             = 0;
diff --git a/apps/openmw/mwgui/mapwindow.cpp b/apps/openmw/mwgui/mapwindow.cpp
index 021cb5cc7d..733a564db5 100644
--- a/apps/openmw/mwgui/mapwindow.cpp
+++ b/apps/openmw/mwgui/mapwindow.cpp
@@ -897,7 +897,6 @@ namespace MWGui
             clickedId.mIndex.mY = y;
         }
         mEditingMarker.mCell = clickedId.getCellRefId();
-        mEditingMarker.mCellId = clickedId;
 
         mEditNoteDialog.setVisible(true);
         mEditNoteDialog.showDeleteButton(false);
diff --git a/apps/openmw/mwworld/cell.hpp b/apps/openmw/mwworld/cell.hpp
index 4b8e9b7639..eb5a4e0de7 100644
--- a/apps/openmw/mwworld/cell.hpp
+++ b/apps/openmw/mwworld/cell.hpp
@@ -5,12 +5,10 @@
 
 #include <components/esm/esmbridge.hpp>
 #include <components/esm/refid.hpp>
-#include <components/esm3/cellid.hpp>
 
 namespace ESM
 {
     struct Cell;
-    struct CellId;
 }
 
 namespace ESM4
diff --git a/apps/openmw/mwworld/cellref.cpp b/apps/openmw/mwworld/cellref.cpp
index 02dd0ec4c4..49d21f4b0e 100644
--- a/apps/openmw/mwworld/cellref.cpp
+++ b/apps/openmw/mwworld/cellref.cpp
@@ -90,11 +90,11 @@ namespace MWWorld
             else
             {
                 const osg::Vec2i index = positionToCellIndex(ref.mDoorDest.pos[0], ref.mDoorDest.pos[1]);
-                ESM::CellId CellId;
-                CellId.mPaged = true;
-                CellId.mIndex.mX = index.x();
-                CellId.mIndex.mY = index.y();
-                return CellId.getCellRefId();
+                ESM::CellId cellId;
+                cellId.mPaged = true;
+                cellId.mIndex.mX = index.x();
+                cellId.mIndex.mY = index.y();
+                return cellId.getCellRefId();
             }
         };
 
diff --git a/apps/openmw/mwworld/cellstore.cpp b/apps/openmw/mwworld/cellstore.cpp
index cf438ede74..6a2689c864 100644
--- a/apps/openmw/mwworld/cellstore.cpp
+++ b/apps/openmw/mwworld/cellstore.cpp
@@ -988,11 +988,11 @@ namespace MWWorld
 
     void CellStore::saveState(ESM::CellState& state) const
     {
-        state.mId = ESM::CellId::extractFromRefId(mCellVariant.getId());
+        state.mId = mCellVariant.getId();
 
         if (!mCellVariant.isExterior() && mCellVariant.hasWater())
             state.mWaterLevel = mWaterLevel;
-
+        state.mIsInterior = !mCellVariant.isExterior();
         state.mHasFogOfWar = (mFogState.get() ? 1 : 0);
         state.mLastRespawn = mLastRespawn.toEsm();
     }
@@ -1019,10 +1019,10 @@ namespace MWWorld
         for (const auto& [base, store] : mMovedToAnotherCell)
         {
             ESM::RefNum refNum = base->mRef.getRefNum();
-            ESM::CellId movedTo = ESM::CellId::extractFromRefId(store->getCell()->getId());
+            ESM::RefId movedTo = store->getCell()->getId();
 
             refNum.save(writer, true, "MVRF");
-            movedTo.save(writer);
+            writer.writeCellId(movedTo);
         }
     }
 
@@ -1078,10 +1078,8 @@ namespace MWWorld
         {
             reader.cacheSubName();
             ESM::RefNum refnum;
-            ESM::CellId movedTo;
             refnum.load(reader, true, "MVRF");
-            movedTo.load(reader);
-            ESM::RefId movedToId = movedTo.getCellRefId();
+            ESM::RefId movedToId = reader.getCellId();
             if (refnum.hasContentFile())
             {
                 auto iter = contentFileMap.find(refnum.mContentFile);
@@ -1103,7 +1101,7 @@ namespace MWWorld
             if (otherCell == nullptr)
             {
                 Log(Debug::Warning) << "Warning: Dropping moved ref tag for " << movedRef.getCellRef().getRefId()
-                                    << " (target cell " << movedTo.mWorldspace
+                                    << " (target cell " << movedToId
                                     << " no longer exists). Reference moved back to its original location.";
                 // Note by dropping tag the object will automatically re-appear in its original cell, though
                 // potentially at inapproriate coordinates. Restore original coordinates:
diff --git a/apps/openmw/mwworld/cellstore.hpp b/apps/openmw/mwworld/cellstore.hpp
index d65b279bdf..451f480e51 100644
--- a/apps/openmw/mwworld/cellstore.hpp
+++ b/apps/openmw/mwworld/cellstore.hpp
@@ -27,7 +27,6 @@ namespace ESM
     class ReadersCache;
     struct Cell;
     struct CellState;
-    struct CellId;
     struct RefNum;
     struct Activator;
     struct Potion;
diff --git a/apps/openmw/mwworld/groundcoverstore.cpp b/apps/openmw/mwworld/groundcoverstore.cpp
index 6c7ab295b6..05777bb816 100644
--- a/apps/openmw/mwworld/groundcoverstore.cpp
+++ b/apps/openmw/mwworld/groundcoverstore.cpp
@@ -51,7 +51,7 @@ namespace MWWorld
         {
             if (!cell.isExterior())
                 continue;
-            auto cellIndex = std::make_pair(cell.getCellId().mIndex.mX, cell.getCellId().mIndex.mY);
+            auto cellIndex = std::make_pair(cell.getGridX(), cell.getGridY());
             mCellContexts[cellIndex] = std::move(cell.mContextList);
         }
     }
diff --git a/apps/openmw/mwworld/player.cpp b/apps/openmw/mwworld/player.cpp
index f0a3f548a5..8507f73389 100644
--- a/apps/openmw/mwworld/player.cpp
+++ b/apps/openmw/mwworld/player.cpp
@@ -283,7 +283,7 @@ namespace MWWorld
         ESM::Player player;
 
         mPlayer.save(player.mObject);
-        player.mCellId = ESM::CellId::extractFromRefId(mCellStore->getCell()->getId());
+        player.mCellId = mCellStore->getCell()->getId();
 
         player.mCurrentCrimeId = mCurrentCrimeId;
         player.mPaidCrimeId = mPaidCrimeId;
@@ -298,7 +298,7 @@ namespace MWWorld
         {
             player.mHasMark = true;
             player.mMarkedPosition = mMarkedPosition;
-            player.mMarkedCell = ESM::CellId::extractFromRefId(mMarkedCell->getCell()->getId());
+            player.mMarkedCell = mMarkedCell->getCell()->getId();
         }
         else
             player.mHasMark = false;
@@ -367,11 +367,11 @@ namespace MWWorld
 
             try
             {
-                mCellStore = MWBase::Environment::get().getWorldModel()->getCellFromCellId(player.mCellId);
+                mCellStore = MWBase::Environment::get().getWorldModel()->getCell(player.mCellId);
             }
             catch (...)
             {
-                Log(Debug::Warning) << "Warning: Player cell '" << player.mCellId.mWorldspace << "' no longer exists";
+                Log(Debug::Warning) << "Warning: Player cell '" << player.mCellId << "' no longer exists";
                 // Cell no longer exists. The loader will have to choose a default cell.
                 mCellStore = nullptr;
             }
@@ -392,19 +392,20 @@ namespace MWWorld
             mLastKnownExteriorPosition.y() = player.mLastKnownExteriorPosition[1];
             mLastKnownExteriorPosition.z() = player.mLastKnownExteriorPosition[2];
 
-            if (player.mHasMark && !player.mMarkedCell.mPaged)
+            bool exterior = ESM::CellId::extractFromRefId(player.mMarkedCell).mPaged;
+            if (player.mHasMark && !exterior)
             {
                 // interior cell -> need to check if it exists (exterior cell will be
                 // generated on the fly)
 
-                if (!world.getStore().get<ESM::Cell>().search(player.mMarkedCell.mWorldspace))
+                if (!world.getStore().get<ESM::Cell>().search(player.mMarkedCell))
                     player.mHasMark = false; // drop mark silently
             }
 
             if (player.mHasMark)
             {
                 mMarkedPosition = player.mMarkedPosition;
-                mMarkedCell = MWBase::Environment::get().getWorldModel()->getCellFromCellId(player.mMarkedCell);
+                mMarkedCell = MWBase::Environment::get().getWorldModel()->getCell(player.mMarkedCell);
             }
             else
             {
diff --git a/apps/openmw/mwworld/store.cpp b/apps/openmw/mwworld/store.cpp
index 16ff60db61..712ec95d1a 100644
--- a/apps/openmw/mwworld/store.cpp
+++ b/apps/openmw/mwworld/store.cpp
@@ -575,9 +575,6 @@ namespace MWWorld
         newCell.mAmbi.mSunlight = 0;
         newCell.mAmbi.mFog = 0;
         newCell.mAmbi.mFogDensity = 0;
-        newCell.mCellId.mPaged = true;
-        newCell.mCellId.mIndex.mX = x;
-        newCell.mCellId.mIndex.mY = y;
         newCell.updateId();
 
         ESM::Cell* newCellInserted = &mCells.insert(std::make_pair(newCell.mId, newCell)).first->second;
diff --git a/apps/openmw/mwworld/worldimp.cpp b/apps/openmw/mwworld/worldimp.cpp
index 2af2ae7faf..7515404037 100644
--- a/apps/openmw/mwworld/worldimp.cpp
+++ b/apps/openmw/mwworld/worldimp.cpp
@@ -380,10 +380,10 @@ namespace MWWorld
                 pos.rot[2] = 0;
 
                 osg::Vec2i exteriorCellPos = positionToCellIndex(pos.pos[0], pos.pos[1]);
-                ESM::CellId CellId;
-                CellId.mPaged = true;
-                CellId.mIndex = { exteriorCellPos.x(), exteriorCellPos.y() };
-                mWorldScene->changeToExteriorCell(CellId.getCellRefId(), pos, true);
+                ESM::CellId cellId;
+                cellId.mPaged = true;
+                cellId.mIndex = { exteriorCellPos.x(), exteriorCellPos.y() };
+                mWorldScene->changeToExteriorCell(cellId.getCellRefId(), pos, true);
             }
         }
 
@@ -987,28 +987,14 @@ namespace MWWorld
         }
         removeContainerScripts(getPlayerPtr());
         osg::Vec2i exteriorCellPos = positionToCellIndex(position.pos[0], position.pos[1]);
-        ESM::CellId CellId;
-        CellId.mPaged = true;
-        CellId.mIndex = { exteriorCellPos.x(), exteriorCellPos.y() };
-        mWorldScene->changeToExteriorCell(CellId.getCellRefId(), position, adjustPlayerPos, changeEvent);
+        ESM::CellId cellId;
+        cellId.mPaged = true;
+        cellId.mIndex = { exteriorCellPos.x(), exteriorCellPos.y() };
+        mWorldScene->changeToExteriorCell(cellId.getCellRefId(), position, adjustPlayerPos, changeEvent);
         addContainerScripts(getPlayerPtr(), getPlayerPtr().getCell());
         mRendering->getCamera()->instantTransition();
     }
 
-    void World::changeToCell(
-        const ESM::CellId& cellId, const ESM::Position& position, bool adjustPlayerPos, bool changeEvent)
-    {
-        if (!changeEvent)
-            mCurrentWorldSpace = cellId.mWorldspace;
-
-        if (cellId.mPaged)
-            changeToExteriorCell(position, adjustPlayerPos, changeEvent);
-        else
-            changeToInteriorCell(cellId.mWorldspace, position, adjustPlayerPos, changeEvent);
-
-        mCurrentDate->setup(mGlobalVariables);
-    }
-
     void World::changeToCell(
         const ESM::RefId& cellId, const ESM::Position& position, bool adjustPlayerPos, bool changeEvent)
     {
diff --git a/apps/openmw/mwworld/worldimp.hpp b/apps/openmw/mwworld/worldimp.hpp
index e2b57c8a1a..dac6df120c 100644
--- a/apps/openmw/mwworld/worldimp.hpp
+++ b/apps/openmw/mwworld/worldimp.hpp
@@ -349,9 +349,6 @@ namespace MWWorld
         ///< Move to exterior cell.
         ///< @param changeEvent If false, do not trigger cell change flag or detect worldspace changes
 
-        void changeToCell(const ESM::CellId& cellId, const ESM::Position& position, bool adjustPlayerPos,
-            bool changeEvent = true) override;
-
         void changeToCell(const ESM::RefId& cellId, const ESM::Position& position, bool adjustPlayerPos,
             bool changeEvent = true) override;
         ///< @param changeEvent If false, do not trigger cell change flag or detect worldspace changes
diff --git a/apps/openmw/mwworld/worldmodel.cpp b/apps/openmw/mwworld/worldmodel.cpp
index 65aeca3bec..a067280519 100644
--- a/apps/openmw/mwworld/worldmodel.cpp
+++ b/apps/openmw/mwworld/worldmodel.cpp
@@ -143,7 +143,8 @@ void MWWorld::WorldModel::writeCell(ESM::ESMWriter& writer, CellStore& cell) con
     cell.saveState(cellState);
 
     writer.startRecord(ESM::REC_CSTA);
-    cellState.mId.save(writer);
+
+    writer.writeCellId(cellState.mId);
     cellState.save(writer);
     cell.writeFog(writer);
     cell.writeReferences(writer);
@@ -170,11 +171,6 @@ MWWorld::CellStore* MWWorld::WorldModel::getExterior(int x, int y)
         {
             // Cell isn't predefined. Make one on the fly.
             ESM::Cell record;
-            record.mCellId.mWorldspace = ESM::CellId::sDefaultWorldspace;
-            record.mCellId.mPaged = true;
-            record.mCellId.mIndex.mX = x;
-            record.mCellId.mIndex.mY = y;
-
             record.mData.mFlags = ESM::Cell::HasWater;
             record.mData.mX = x;
             record.mData.mY = y;
@@ -227,14 +223,6 @@ MWWorld::CellStore* MWWorld::WorldModel::getInterior(std::string_view name)
     return result->second;
 }
 
-MWWorld::CellStore* MWWorld::WorldModel::getCellFromCellId(const ESM::CellId& id)
-{
-    if (id.mPaged)
-        return getExterior(id.mIndex.mX, id.mIndex.mY);
-
-    return getInterior(id.mWorldspace);
-}
-
 MWWorld::CellStore* MWWorld::WorldModel::getCell(const ESM::RefId& id)
 {
     auto result = mCells.find(id);
@@ -489,19 +477,18 @@ bool MWWorld::WorldModel::readRecord(ESM::ESMReader& reader, uint32_t type, cons
     if (type == ESM::REC_CSTA)
     {
         ESM::CellState state;
-        state.mId.load(reader);
+        state.mId = reader.getCellId();
 
         CellStore* cellStore = nullptr;
 
         try
         {
-            cellStore = getCell(state.mId.getCellRefId());
+            cellStore = getCell(state.mId);
         }
         catch (...)
         {
             // silently drop cells that don't exist anymore
-            Log(Debug::Warning) << "Warning: Dropping state for cell " << state.mId.mWorldspace
-                                << " (cell no longer exists)";
+            Log(Debug::Warning) << "Warning: Dropping state for cell " << state.mId << " (cell no longer exists)";
             reader.skipRecord();
             return true;
         }
diff --git a/apps/openmw/mwworld/worldmodel.hpp b/apps/openmw/mwworld/worldmodel.hpp
index 04afff0095..10292c3ca5 100644
--- a/apps/openmw/mwworld/worldmodel.hpp
+++ b/apps/openmw/mwworld/worldmodel.hpp
@@ -17,7 +17,6 @@ namespace ESM
     class ESMReader;
     class ESMWriter;
     class ReadersCache;
-    struct CellId;
     struct Cell;
     struct RefNum;
 }
@@ -71,7 +70,6 @@ namespace MWWorld
         CellStore* getInterior(std::string_view name);
         CellStore* getCell(std::string_view name); // interior or named exterior
         CellStore* getCell(const ESM::RefId& Id);
-        CellStore* getCellFromCellId(const ESM::CellId& Id);
 
         // If cellNameInSameWorldSpace is an interior - returns this interior.
         // Otherwise returns exterior cell for given position in the same world space.
diff --git a/components/esm/esmbridge.hpp b/components/esm/esmbridge.hpp
index ee6238cbc6..26283bb44f 100644
--- a/components/esm/esmbridge.hpp
+++ b/components/esm/esmbridge.hpp
@@ -15,7 +15,6 @@ namespace ESM4
 namespace ESM
 {
     struct Cell;
-    struct CellId;
     class RefId;
 
     class CellVariant;
diff --git a/components/esm3/cellstate.cpp b/components/esm3/cellstate.cpp
index 830a4211b6..7855aeac40 100644
--- a/components/esm3/cellstate.cpp
+++ b/components/esm3/cellstate.cpp
@@ -21,7 +21,7 @@ namespace ESM
 
     void CellState::save(ESMWriter& esm) const
     {
-        if (!mId.mPaged)
+        if (mIsInterior)
             esm.writeHNT("WLVL", mWaterLevel);
 
         esm.writeHNT("HFOW", mHasFogOfWar);
diff --git a/components/esm3/cellstate.hpp b/components/esm3/cellstate.hpp
index 2f721b3838..703e31e81b 100644
--- a/components/esm3/cellstate.hpp
+++ b/components/esm3/cellstate.hpp
@@ -15,8 +15,8 @@ namespace ESM
     /// \note Does not include references
     struct CellState
     {
-        CellId mId;
-
+        RefId mId;
+        bool mIsInterior;
         float mWaterLevel;
 
         int mHasFogOfWar; // Do we have fog of war state (0 or 1)? (see fogstate.hpp)
diff --git a/components/esm3/custommarkerstate.cpp b/components/esm3/custommarkerstate.cpp
index 4568cfa748..a45a6a73a6 100644
--- a/components/esm3/custommarkerstate.cpp
+++ b/components/esm3/custommarkerstate.cpp
@@ -10,7 +10,7 @@ namespace ESM
     {
         esm.writeHNT("POSX", mWorldX);
         esm.writeHNT("POSY", mWorldY);
-        mCellId.save(esm);
+        esm.writeCellId(mCell);
         if (!mNote.empty())
             esm.writeHNString("NOTE", mNote);
     }
@@ -19,8 +19,7 @@ namespace ESM
     {
         esm.getHNT(mWorldX, "POSX");
         esm.getHNT(mWorldY, "POSY");
-        mCellId.load(esm);
-        mCell = mCellId.getCellRefId();
+        mCell = esm.getCellId();
         mNote = esm.getHNOString("NOTE");
     }
 
diff --git a/components/esm3/custommarkerstate.hpp b/components/esm3/custommarkerstate.hpp
index e1a129ffbe..1c0822277b 100644
--- a/components/esm3/custommarkerstate.hpp
+++ b/components/esm3/custommarkerstate.hpp
@@ -13,7 +13,6 @@ namespace ESM
         float mWorldY;
 
         RefId mCell;
-        CellId mCellId; // The CellId representation for saving/loading
 
         std::string mNote;
 
diff --git a/components/esm3/esmreader.cpp b/components/esm3/esmreader.cpp
index 20ec9e47b8..5f618903c4 100644
--- a/components/esm3/esmreader.cpp
+++ b/components/esm3/esmreader.cpp
@@ -3,6 +3,7 @@
 #include "readerscache.hpp"
 #include "savedgame.hpp"
 
+#include <components/esm3/cellid.hpp>
 #include <components/files/conversion.hpp>
 #include <components/files/openfile.hpp>
 #include <components/misc/strings/algorithm.hpp>
@@ -86,6 +87,13 @@ namespace ESM
         }
     }
 
+    ESM::RefId ESMReader::getCellId()
+    {
+        ESM::CellId cellId;
+        cellId.load(*this);
+        return cellId.getCellRefId();
+    }
+
     void ESMReader::openRaw(std::unique_ptr<std::istream>&& stream, const std::filesystem::path& name)
     {
         close();
diff --git a/components/esm3/esmreader.hpp b/components/esm3/esmreader.hpp
index 3e667e6972..703f10be0c 100644
--- a/components/esm3/esmreader.hpp
+++ b/components/esm3/esmreader.hpp
@@ -96,6 +96,9 @@ namespace ESM
          *
          *************************************************************************/
 
+        // Because we want to get rid of CellId, we isolate it's uses.
+        ESM::RefId getCellId();
+
         // Read data of a given type, stored in a subrecord of a given name
         template <typename X>
         void getHNT(X& x, NAME name)
diff --git a/components/esm3/esmwriter.cpp b/components/esm3/esmwriter.cpp
index 02c7464b33..db84f58332 100644
--- a/components/esm3/esmwriter.cpp
+++ b/components/esm3/esmwriter.cpp
@@ -4,6 +4,7 @@
 #include <fstream>
 #include <stdexcept>
 
+#include <components/esm3/cellid.hpp>
 #include <components/debug/debuglog.hpp>
 #include <components/misc/notnullptr.hpp>
 #include <components/to_utf8/to_utf8.hpp>
@@ -236,6 +237,12 @@ namespace ESM
         writeHNRefId(name, value);
     }
 
+    void ESMWriter::writeCellId(const ESM::RefId& cellId)
+    {
+        ESM::CellId cell = ESM::CellId::extractFromRefId(cellId);
+        cell.save(*this);
+    }
+
     void ESMWriter::writeMaybeFixedSizeString(const std::string& data, std::size_t size)
     {
         std::string string;
diff --git a/components/esm3/esmwriter.hpp b/components/esm3/esmwriter.hpp
index 54abca41f2..acf9488d9a 100644
--- a/components/esm3/esmwriter.hpp
+++ b/components/esm3/esmwriter.hpp
@@ -103,6 +103,8 @@ namespace ESM
                 writeHNCRefId(name, value);
         }
 
+        void writeCellId(const ESM::RefId& cellId);
+
         template <typename T>
         void writeHNT(NAME name, const T& data)
         {
diff --git a/components/esm3/loadcell.cpp b/components/esm3/loadcell.cpp
index 2c6060ce8a..6db783d5c6 100644
--- a/components/esm3/loadcell.cpp
+++ b/components/esm3/loadcell.cpp
@@ -59,7 +59,23 @@ namespace ESM
 
     const ESM::RefId& Cell::updateId()
     {
-        mId = mCellId.getCellRefId();
+        CellId cellid;
+
+        cellid.mPaged = !(mData.mFlags & Interior);
+
+        if (cellid.mPaged)
+        {
+            cellid.mWorldspace = CellId::sDefaultWorldspace;
+            cellid.mIndex.mX = mData.mX;
+            cellid.mIndex.mY = mData.mY;
+        }
+        else
+        {
+            cellid.mWorldspace = Misc::StringUtils::lowerCase(mName);
+            cellid.mIndex.mX = 0;
+            cellid.mIndex.mY = 0;
+        }
+        mId = cellid.getCellRefId();
         return mId;
     }
 
@@ -97,20 +113,6 @@ namespace ESM
         if (!hasData)
             esm.fail("Missing DATA subrecord");
 
-        mCellId.mPaged = !(mData.mFlags & Interior);
-
-        if (mCellId.mPaged)
-        {
-            mCellId.mWorldspace = CellId::sDefaultWorldspace;
-            mCellId.mIndex.mX = mData.mX;
-            mCellId.mIndex.mY = mData.mY;
-        }
-        else
-        {
-            mCellId.mWorldspace = Misc::StringUtils::lowerCase(mName);
-            mCellId.mIndex.mX = 0;
-            mCellId.mIndex.mY = 0;
-        }
         updateId();
     }
 
@@ -340,8 +342,4 @@ namespace ESM
         mAmbi.mFogDensity = 0;
     }
 
-    const CellId& Cell::getCellId() const
-    {
-        return mCellId;
-    }
 }
diff --git a/components/esm3/loadcell.hpp b/components/esm3/loadcell.hpp
index f49f4f083a..d59186b6f0 100644
--- a/components/esm3/loadcell.hpp
+++ b/components/esm3/loadcell.hpp
@@ -120,7 +120,6 @@ namespace ESM
 
         std::vector<ESM_Context> mContextList; // File position; multiple positions for multiple plugin support
         DATAstruct mData;
-        CellId mCellId;
 
         AMBIstruct mAmbi;
         bool mHasAmbi;
@@ -191,7 +190,6 @@ namespace ESM
         void blank();
         ///< Set record to default state (does not touch the ID/index).
 
-        const CellId& getCellId() const;
         const ESM::RefId& updateId();
     };
 }
diff --git a/components/esm3/player.cpp b/components/esm3/player.cpp
index 0a25886ce0..4c56c7488b 100644
--- a/components/esm3/player.cpp
+++ b/components/esm3/player.cpp
@@ -11,7 +11,7 @@ namespace ESM
         mObject.mRef.loadId(esm, true);
         mObject.load(esm);
 
-        mCellId.load(esm);
+        mCellId = esm.getCellId();
 
         esm.getHNTSized<12>(mLastKnownExteriorPosition, "LKEP");
 
@@ -19,7 +19,7 @@ namespace ESM
         {
             mHasMark = true;
             esm.getHTSized<24>(mMarkedPosition);
-            mMarkedCell.load(esm);
+            mMarkedCell = esm.getCellId();
         }
         else
             mHasMark = false;
@@ -92,14 +92,14 @@ namespace ESM
     {
         mObject.save(esm);
 
-        mCellId.save(esm);
+        esm.writeCellId(mCellId);
 
         esm.writeHNT("LKEP", mLastKnownExteriorPosition);
 
         if (mHasMark)
         {
             esm.writeHNT("MARK", mMarkedPosition, 24);
-            mMarkedCell.save(esm);
+            esm.writeCellId(mMarkedCell);
         }
 
         esm.writeHNRefId("SIGN", mBirthsign);
diff --git a/components/esm3/player.hpp b/components/esm3/player.hpp
index 82ce5e25df..25d9c76fce 100644
--- a/components/esm3/player.hpp
+++ b/components/esm3/player.hpp
@@ -20,12 +20,12 @@ namespace ESM
     struct Player
     {
         NpcState mObject;
-        CellId mCellId;
+        RefId mCellId;
         float mLastKnownExteriorPosition[3];
         unsigned char mHasMark;
         bool mSetWerewolfAcrobatics;
         Position mMarkedPosition;
-        CellId mMarkedCell;
+        RefId mMarkedCell;
         ESM::RefId mBirthsign;
 
         int mCurrentCrimeId;
diff --git a/components/esmloader/load.cpp b/components/esmloader/load.cpp
index 46fe3717a4..5b1888f2ce 100644
--- a/components/esmloader/load.cpp
+++ b/components/esmloader/load.cpp
@@ -45,7 +45,7 @@ namespace EsmLoader
                 return (v.mId);
             }
 
-            const ESM::CellId& operator()(const ESM::Cell& v) const { return v.mCellId; }
+            const ESM::RefId& operator()(const ESM::Cell& v) const { return v.mId; }
 
             std::pair<int, int> operator()(const ESM::Land& v) const { return std::pair(v.mX, v.mY); }