diff --git a/src/openrct2/interface/Colour.h b/src/openrct2/interface/Colour.h
index 0ae29c6492..26a98eccb3 100644
--- a/src/openrct2/interface/Colour.h
+++ b/src/openrct2/interface/Colour.h
@@ -13,6 +13,8 @@
 
 #include <string_view>
 
+using PaletteIndex = uint8_t;
+
 /**
  * Colour IDs as used by the colour dropdown, NOT palette indices.
  */
@@ -65,7 +67,7 @@ enum
     COLOUR_LIGHT_WATER = 10
 };
 
-enum : uint8_t
+enum : PaletteIndex
 {
     PALETTE_INDEX_0 = 0,     // Transparent
     PALETTE_INDEX_10 = 10,   // Black (0-dark), Dark grey (0)
diff --git a/src/openrct2/object/TerrainSurfaceObject.h b/src/openrct2/object/TerrainSurfaceObject.h
index 0cbce2d7ba..9663e7d40b 100644
--- a/src/openrct2/object/TerrainSurfaceObject.h
+++ b/src/openrct2/object/TerrainSurfaceObject.h
@@ -53,7 +53,7 @@ public:
     uint8_t Rotations{};
     money32 Price{};
     TERRAIN_SURFACE_FLAGS Flags{};
-    uint8_t MapColours[2];
+    PaletteIndex MapColours[2];
 
     void ReadJson(IReadObjectContext* context, json_t& root) override;
     void Load() override;