diff --git a/apps/openmw/mwbase/world.hpp b/apps/openmw/mwbase/world.hpp
index 71bb85c798..e0d64fba9f 100644
--- a/apps/openmw/mwbase/world.hpp
+++ b/apps/openmw/mwbase/world.hpp
@@ -316,7 +316,8 @@ namespace MWBase
         /// relative to \a referenceObject (but the object may be placed somewhere else if the wanted location is
         /// obstructed).
 
-        virtual void indexToPosition(int cellX, int cellY, float& x, float& y, bool centre = false) const = 0;
+        virtual void indexToPosition(
+            int cellX, int cellY, float& x, float& y, bool centre = false, bool esm4Exterior = false) const = 0;
         ///< Convert cell numbers to position.
 
         virtual void queueMovement(const MWWorld::Ptr& ptr, const osg::Vec3f& velocity) = 0;
diff --git a/apps/openmw/mwphysics/physicssystem.cpp b/apps/openmw/mwphysics/physicssystem.cpp
index d2076a6280..5f4c09842a 100644
--- a/apps/openmw/mwphysics/physicssystem.cpp
+++ b/apps/openmw/mwphysics/physicssystem.cpp
@@ -483,8 +483,10 @@ namespace MWPhysics
             mHeightFields.erase(heightfield);
     }
 
-    const HeightField* PhysicsSystem::getHeightField(int x, int y) const
+    const HeightField* PhysicsSystem::getHeightField(int x, int y, ESM::RefId worldspace) const
     {
+        if (worldspace != ESM::Cell::sDefaultWorldspaceId)
+            return nullptr;
         const auto heightField = mHeightFields.find(std::make_pair(x, y));
         if (heightField == mHeightFields.end())
             return nullptr;
diff --git a/apps/openmw/mwphysics/physicssystem.hpp b/apps/openmw/mwphysics/physicssystem.hpp
index 923ace45bb..d61b0f38d9 100644
--- a/apps/openmw/mwphysics/physicssystem.hpp
+++ b/apps/openmw/mwphysics/physicssystem.hpp
@@ -189,7 +189,7 @@ namespace MWPhysics
 
         void removeHeightField(int x, int y);
 
-        const HeightField* getHeightField(int x, int y) const;
+        const HeightField* getHeightField(int x, int y, ESM::RefId worldspace) const;
 
         bool toggleCollisionMode();
 
diff --git a/apps/openmw/mwrender/landmanager.cpp b/apps/openmw/mwrender/landmanager.cpp
index 59b9fdbde4..74811677a0 100644
--- a/apps/openmw/mwrender/landmanager.cpp
+++ b/apps/openmw/mwrender/landmanager.cpp
@@ -18,8 +18,11 @@ namespace MWRender
         mCache = new CacheType;
     }
 
-    osg::ref_ptr<ESMTerrain::LandObject> LandManager::getLand(int x, int y)
+    osg::ref_ptr<ESMTerrain::LandObject> LandManager::getLand(int x, int y, ESM::RefId worldspace)
     {
+        if (worldspace != ESM::Cell::sDefaultWorldspaceId)
+            return osg::ref_ptr<ESMTerrain::LandObject>(nullptr);
+
         osg::ref_ptr<osg::Object> obj = mCache->getRefFromObjectCache(std::make_pair(x, y));
         if (obj)
             return static_cast<ESMTerrain::LandObject*>(obj.get());
diff --git a/apps/openmw/mwrender/landmanager.hpp b/apps/openmw/mwrender/landmanager.hpp
index 4c00cefe9b..959647fadc 100644
--- a/apps/openmw/mwrender/landmanager.hpp
+++ b/apps/openmw/mwrender/landmanager.hpp
@@ -20,7 +20,7 @@ namespace MWRender
         LandManager(int loadFlags);
 
         /// @note Will return nullptr if not found.
-        osg::ref_ptr<ESMTerrain::LandObject> getLand(int x, int y);
+        osg::ref_ptr<ESMTerrain::LandObject> getLand(int x, int y, ESM::RefId worldspace);
 
         void reportStats(unsigned int frameNumber, osg::Stats* stats) const override;
 
diff --git a/apps/openmw/mwrender/terrainstorage.cpp b/apps/openmw/mwrender/terrainstorage.cpp
index c85ee62f88..e23efbd2a3 100644
--- a/apps/openmw/mwrender/terrainstorage.cpp
+++ b/apps/openmw/mwrender/terrainstorage.cpp
@@ -68,7 +68,7 @@ namespace MWRender
 
     osg::ref_ptr<const ESMTerrain::LandObject> TerrainStorage::getLand(int cellX, int cellY)
     {
-        return mLandManager->getLand(cellX, cellY);
+        return mLandManager->getLand(cellX, cellY, ESM::Cell::sDefaultWorldspaceId);
     }
 
     const ESM::LandTexture* TerrainStorage::getLandTexture(int index, short plugin)
diff --git a/apps/openmw/mwworld/cellpreloader.cpp b/apps/openmw/mwworld/cellpreloader.cpp
index 3ba20d635e..0e2e773b74 100644
--- a/apps/openmw/mwworld/cellpreloader.cpp
+++ b/apps/openmw/mwworld/cellpreloader.cpp
@@ -102,7 +102,7 @@ namespace MWWorld
                 try
                 {
                     mTerrain->cacheCell(mTerrainView.get(), mX, mY);
-                    mPreloadedObjects.insert(mLandManager->getLand(mX, mY));
+                    mPreloadedObjects.insert(mLandManager->getLand(mX, mY, ESM::Cell::sDefaultWorldspaceId));
                 }
                 catch (std::exception&)
                 {
diff --git a/apps/openmw/mwworld/cellutils.hpp b/apps/openmw/mwworld/cellutils.hpp
index a7e8e88c78..978e358c8b 100644
--- a/apps/openmw/mwworld/cellutils.hpp
+++ b/apps/openmw/mwworld/cellutils.hpp
@@ -9,10 +9,10 @@
 
 namespace MWWorld
 {
-    inline osg::Vec2i positionToCellIndex(float x, float y)
+    inline osg::Vec2i positionToCellIndex(float x, float y, bool esm4Ext = false)
     {
-        return { static_cast<int>(std::floor(x / Constants::CellSizeInUnits)),
-            static_cast<int>(std::floor(y / Constants::CellSizeInUnits)) };
+        const float cellSize = esm4Ext ? Constants::ESM4CellSizeInUnits : Constants::CellSizeInUnits;
+        return { static_cast<int>(std::floor(x / cellSize)), static_cast<int>(std::floor(y / cellSize)) };
     }
 }
 
diff --git a/apps/openmw/mwworld/scene.cpp b/apps/openmw/mwworld/scene.cpp
index d0f755fece..ec63e6429b 100644
--- a/apps/openmw/mwworld/scene.cpp
+++ b/apps/openmw/mwworld/scene.cpp
@@ -13,6 +13,7 @@
 #include <components/detournavigator/navigator.hpp>
 #include <components/detournavigator/updateguard.hpp>
 #include <components/esm/records.hpp>
+#include <components/esm3/loadcell.hpp>
 #include <components/loadinglistener/loadinglistener.hpp>
 #include <components/misc/convert.hpp>
 #include <components/misc/resourcehelpers.hpp>
@@ -247,12 +248,13 @@ namespace
         return std::abs(cellPosition.first) + std::abs(cellPosition.second);
     }
 
-    bool isCellInCollection(int x, int y, MWWorld::Scene::CellStoreCollection& collection)
+    bool isCellInCollection(int x, int y, ESM::RefId worldspace, MWWorld::Scene::CellStoreCollection& collection)
     {
         for (auto* cell : collection)
         {
             assert(cell->getCell()->isExterior());
-            if (x == cell->getCell()->getGridX() && y == cell->getCell()->getGridY())
+            if (x == cell->getCell()->getGridX() && y == cell->getCell()->getGridY()
+                && cell->getCell()->getWorldSpace() == worldspace)
                 return true;
         }
         return false;
@@ -346,7 +348,7 @@ namespace MWWorld
 
         if (cell->getCell()->isExterior())
         {
-            if (mPhysics->getHeightField(cellX, cellY) != nullptr)
+            if (mPhysics->getHeightField(cellX, cellY, cell->getCell()->getWorldSpace()) != nullptr)
                 mNavigator.removeHeightfield(osg::Vec2i(cellX, cellY), navigatorUpdateGuard);
 
             mPhysics->removeHeightField(cellX, cellY);
@@ -391,10 +393,12 @@ namespace MWWorld
         const int cellX = cell.getCell()->getGridX();
         const int cellY = cell.getCell()->getGridY();
         const MWWorld::Cell& cellVariant = *cell.getCell();
+        ESM::RefId worldspace = cellVariant.getWorldSpace();
 
         if (cellVariant.isExterior())
         {
-            osg::ref_ptr<const ESMTerrain::LandObject> land = mRendering.getLandManager()->getLand(cellX, cellY);
+            osg::ref_ptr<const ESMTerrain::LandObject> land
+                = mRendering.getLandManager()->getLand(cellX, cellY, worldspace);
             const ESM::Land::LandData* data = land ? land->getData(ESM::Land::DATA_VHGT) : nullptr;
             const int verts = ESM::Land::LAND_SIZE;
             const int worldsize = ESM::Land::REAL_SIZE;
@@ -410,7 +414,7 @@ namespace MWWorld
                 mPhysics->addHeightField(defaultHeight.data(), cellX, cellY, worldsize, verts,
                     ESM::Land::DEFAULT_HEIGHT, ESM::Land::DEFAULT_HEIGHT, land.get());
             }
-            if (const auto heightField = mPhysics->getHeightField(cellX, cellY))
+            if (const auto heightField = mPhysics->getHeightField(cellX, cellY, worldspace))
             {
                 const osg::Vec2i cellPosition(cellX, cellY);
                 const btVector3& origin = heightField->getCollisionObject()->getWorldTransform().getOrigin();
@@ -465,7 +469,7 @@ namespace MWWorld
 
             if (cellVariant.isExterior())
             {
-                if (const auto heightField = mPhysics->getHeightField(cellX, cellY))
+                if (const auto heightField = mPhysics->getHeightField(cellX, cellY, worldspace))
                     mNavigator.addWater(
                         osg::Vec2i(cellX, cellY), ESM::Land::REAL_SIZE, waterLevel, navigatorUpdateGuard);
             }
@@ -507,17 +511,18 @@ namespace MWWorld
 
     osg::Vec2i Scene::getNewGridCenter(const osg::Vec3f& pos, const osg::Vec2i* currentGridCenter) const
     {
+        bool isEsm4Ext = mCurrentCell && mCurrentCell->getCell()->getWorldSpace() != ESM::Cell::sDefaultWorldspaceId;
         if (currentGridCenter)
         {
             float centerX, centerY;
-            mWorld.indexToPosition(currentGridCenter->x(), currentGridCenter->y(), centerX, centerY, true);
+            mWorld.indexToPosition(currentGridCenter->x(), currentGridCenter->y(), centerX, centerY, true, isEsm4Ext);
             float distance = std::max(std::abs(centerX - pos.x()), std::abs(centerY - pos.y()));
             const float maxDistance
                 = Constants::CellSizeInUnits / 2 + mCellLoadingThreshold; // 1/2 cell size + threshold
             if (distance <= maxDistance)
                 return *currentGridCenter;
         }
-        return positionToCellIndex(pos.x(), pos.y());
+        return positionToCellIndex(pos.x(), pos.y(), isEsm4Ext);
     }
 
     void Scene::playerMoved(const osg::Vec3f& pos)
@@ -532,7 +537,8 @@ namespace MWWorld
 
     void Scene::requestChangeCellGrid(const osg::Vec3f& position, const osg::Vec2i& cell, bool changeEvent)
     {
-        mChangeCellGridRequest = ChangeCellGridRequest{ position, cell, ESM::Cell::sDefaultWorldspaceId, changeEvent };
+        mChangeCellGridRequest
+            = ChangeCellGridRequest{ position, cell, mCurrentCell->getCell()->getWorldSpace(), changeEvent };
     }
 
     void Scene::changeCellGrid(
@@ -580,7 +586,7 @@ namespace MWWorld
             {
                 for (int y = playerCellY - range; y <= playerCellY + range; ++y)
                 {
-                    if (!isCellInCollection(x, y, collection))
+                    if (!isCellInCollection(x, y, exteriorWorldspace, collection))
                     {
                         refsToLoad += mWorld.getWorldModel().getExterior(x, y, exteriorWorldspace).count();
                         cellsPositionsToLoad.emplace_back(x, y);
@@ -614,7 +620,7 @@ namespace MWWorld
 
         for (const auto& [x, y] : cellsPositionsToLoad)
         {
-            if (!isCellInCollection(x, y, mActiveCells))
+            if (!isCellInCollection(x, y, exteriorWorldspace, mActiveCells))
             {
                 CellStore& cell = mWorld.getWorldModel().getExterior(x, y, exteriorWorldspace);
                 loadCell(cell, loadingListener, changeEvent, pos, navigatorUpdateGuard.get());
diff --git a/apps/openmw/mwworld/worldimp.cpp b/apps/openmw/mwworld/worldimp.cpp
index 8f38a9e081..ff1b7842f7 100644
--- a/apps/openmw/mwworld/worldimp.cpp
+++ b/apps/openmw/mwworld/worldimp.cpp
@@ -1512,9 +1512,9 @@ namespace MWWorld
         return placed;
     }
 
-    void World::indexToPosition(int cellX, int cellY, float& x, float& y, bool centre) const
+    void World::indexToPosition(int cellX, int cellY, float& x, float& y, bool centre, bool esm4Ext) const
     {
-        const int cellSize = Constants::CellSizeInUnits;
+        const int cellSize = esm4Ext ? Constants::ESM4CellSizeInUnits : Constants::CellSizeInUnits;
 
         x = static_cast<float>(cellSize * cellX);
         y = static_cast<float>(cellSize * cellY);
@@ -2766,7 +2766,8 @@ namespace MWWorld
         {
             int x = ext->getGridX();
             int y = ext->getGridY();
-            indexToPosition(x, y, pos.pos[0], pos.pos[1], true);
+            bool esm4Ext = ext->getWorldSpace() != ESM::Cell::sDefaultWorldspaceId;
+            indexToPosition(x, y, pos.pos[0], pos.pos[1], true, esm4Ext);
 
             // Note: Z pos will be adjusted by adjustPosition later
             pos.pos[2] = 0;
diff --git a/apps/openmw/mwworld/worldimp.hpp b/apps/openmw/mwworld/worldimp.hpp
index c8e9ba5bd8..b181e6d49d 100644
--- a/apps/openmw/mwworld/worldimp.hpp
+++ b/apps/openmw/mwworld/worldimp.hpp
@@ -403,7 +403,8 @@ namespace MWWorld
 
         float getMaxActivationDistance() const override;
 
-        void indexToPosition(int cellX, int cellY, float& x, float& y, bool centre = false) const override;
+        void indexToPosition(
+            int cellX, int cellY, float& x, float& y, bool centre = false, bool esm4Exterior = false) const override;
         ///< Convert cell numbers to position.
 
         void queueMovement(const Ptr& ptr, const osg::Vec3f& velocity) override;
diff --git a/components/misc/constants.hpp b/components/misc/constants.hpp
index deb47a7667..545db87094 100644
--- a/components/misc/constants.hpp
+++ b/components/misc/constants.hpp
@@ -23,6 +23,7 @@ namespace Constants
 
     // Size of one exterior cell in game units
     constexpr int CellSizeInUnits = 8192;
+    constexpr int ESM4CellSizeInUnits = 4096;
 
     // Size of active cell grid in cells (it is a square with the (2 * CellGridRadius + 1) cells side)
     constexpr int CellGridRadius = 1;