diff --git a/OpenRA.Game/Map/CellLayer.cs b/OpenRA.Game/Map/CellLayer.cs
new file mode 100644
index 0000000000..7f973b8902
--- /dev/null
+++ b/OpenRA.Game/Map/CellLayer.cs
@@ -0,0 +1,105 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2014 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation. For more information,
+ * see COPYING.
+ */
+#endregion
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Drawing;
+using OpenRA.Graphics;
+
+namespace OpenRA
+{
+	// Represents a layer of "something" that covers the map
+	public class CellLayer<T> : IEnumerable<T>
+	{
+		public readonly Size Size;
+		T[] entries;
+
+		public CellLayer(Map map)
+			: this(new Size(map.MapSize.X, map.MapSize.Y)) { }
+
+		public CellLayer(Size size)
+		{
+			Size = size;
+			entries = new T[size.Width * size.Height];
+		}
+
+		// Resolve an array index from cell coordinates
+		int Index(CPos cell)
+		{
+			// This will eventually define a distinct case for diagonal cell grids
+			return cell.Y * Size.Width + cell.X;
+		}
+
+		/// <summary>Gets or sets the <see cref="OpenRA.CellLayer"/> using cell coordinates</summary>
+		public T this[CPos cell]
+		{
+			get
+			{
+				return entries[Index(cell)];
+			}
+
+			set
+			{
+				entries[Index(cell)] = value;
+			}
+		}
+
+		/// <summary>Gets or sets the layer contents using raw map coordinates (not CPos!)</summary>
+		public T this[int u, int v]
+		{
+			get
+			{
+				return entries[v * Size.Width + u];
+			}
+
+			set
+			{
+				entries[v * Size.Width + u] = value;
+			}
+		}
+
+		/// <summary>Clears the layer contents with a known value</summary>
+		public void Clear(T clearValue)
+		{
+			for (var i = 0; i < entries.Length; i++)
+				entries[i] = clearValue;
+		}
+
+		public IEnumerator<T> GetEnumerator()
+		{
+			return (IEnumerator<T>)entries.GetEnumerator();
+		}
+
+		IEnumerator IEnumerable.GetEnumerator()
+		{
+			return GetEnumerator();
+		}
+	}
+
+	// Helper functions
+	public static class CellLayer
+	{
+		/// <summary>Create a new layer by resizing another layer.  New cells are filled with defaultValue.</summary>
+		public static CellLayer<T> Resize<T>(CellLayer<T> layer, Size newSize, T defaultValue)
+		{
+			var result = new CellLayer<T>(newSize);
+			var width = Math.Min(layer.Size.Width, newSize.Width);
+			var height = Math.Min(layer.Size.Height, newSize.Height);
+
+			result.Clear(defaultValue);
+			for (var j = 0; j < height; j++)
+				for (var i = 0; i < width; i++)
+					result[i, j] = layer[i, j];
+
+			return result;
+		}
+	}
+}
diff --git a/OpenRA.Game/Map/CellRegion.cs b/OpenRA.Game/Map/CellRegion.cs
new file mode 100644
index 0000000000..3cdccc7fbe
--- /dev/null
+++ b/OpenRA.Game/Map/CellRegion.cs
@@ -0,0 +1,101 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2014 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation. For more information,
+ * see COPYING.
+ */
+#endregion
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Drawing;
+using OpenRA.Graphics;
+
+namespace OpenRA
+{
+	// Represents a (on-screen) rectangular collection of tiles.
+	// TopLeft and BottomRight are inclusive
+	public class CellRegion : IEnumerable<CPos>
+	{
+		// Corners of the region
+		public readonly CPos TopLeft;
+		public readonly CPos BottomRight;
+
+		// Corners in map coordinates
+		// Defined for forward compatibility with diagonal cell grids
+		readonly CPos mapTopLeft;
+		readonly CPos mapBottomRight;
+
+		public CellRegion(CPos topLeft, CPos bottomRight)
+		{
+			TopLeft = topLeft;
+			BottomRight = bottomRight;
+
+			mapTopLeft = TopLeft;
+			mapBottomRight = BottomRight;
+		}
+
+		public bool Contains(CPos cell)
+		{
+			// Defined for forward compatibility with diagonal cell grids
+			var uv = cell;
+			return uv.X >= mapTopLeft.X && uv.X <= mapBottomRight.X && uv.Y >= mapTopLeft.Y && uv.Y <= mapBottomRight.Y;
+		}
+
+		public IEnumerator<CPos> GetEnumerator()
+		{
+			return new CellRegionEnumerator(this);
+		}
+
+		IEnumerator IEnumerable.GetEnumerator()
+		{
+			return GetEnumerator();
+		}
+
+		class CellRegionEnumerator : IEnumerator<CPos>
+		{
+			readonly CellRegion r;
+
+			// Current position, in map coordinates
+			int u, v;
+
+			public CellRegionEnumerator(CellRegion region)
+			{
+				r = region;
+				Reset();
+			}
+
+			public bool MoveNext()
+			{
+				u += 1;
+
+				// Check for column overflow
+				if (u > r.mapBottomRight.X)
+				{
+					v += 1;
+					u = r.mapTopLeft.X;
+
+					// Check for row overflow
+					if (v > r.mapBottomRight.Y)
+						return false;
+				}
+
+				return true;
+			}
+
+			public void Reset()
+			{
+				// Enumerator starts *before* the first element in the sequence.
+				u = r.mapTopLeft.X - 1;
+				v = r.mapTopLeft.Y;
+			}
+
+			public CPos Current { get { return new CPos(u, v); } }
+			object IEnumerator.Current { get { return Current; } }
+			public void Dispose() { }
+		}
+	}
+}
diff --git a/OpenRA.Game/OpenRA.Game.csproj b/OpenRA.Game/OpenRA.Game.csproj
index 0657df79df..d41cd7a7c4 100644
--- a/OpenRA.Game/OpenRA.Game.csproj
+++ b/OpenRA.Game/OpenRA.Game.csproj
@@ -235,6 +235,8 @@
     <Compile Include="Support\MersenneTwister.cs" />
     <Compile Include="GameInformation.cs" />
     <Compile Include="Widgets\RootWidget.cs" />
+    <Compile Include="Map\CellLayer.cs" />
+    <Compile Include="Map\CellRegion.cs" />
   </ItemGroup>
   <ItemGroup>
     <Compile Include="FileSystem\D2kSoundResources.cs" />
@@ -358,4 +360,4 @@
   </Target>
   -->
   <ItemGroup />
-</Project>
\ No newline at end of file
+</Project>