diff --git a/src/openrct2/rct1/S4Importer.cpp b/src/openrct2/rct1/S4Importer.cpp
index d5e96e1f2f..c60234fa38 100644
--- a/src/openrct2/rct1/S4Importer.cpp
+++ b/src/openrct2/rct1/S4Importer.cpp
@@ -462,7 +462,7 @@ private:
 
     void AddAvailableEntriesFromMap()
     {
-        size_t maxTiles = 128 * 128;
+        size_t maxTiles = RCT1_MAX_MAP_SIZE * RCT1_MAX_MAP_SIZE;
         size_t tileIndex = 0;
         RCT12TileElement* tileElement = _s4.tile_elements;