diff --git a/lib/OpenLayers/Layer/TMS.js b/lib/OpenLayers/Layer/TMS.js
index 1291b4dd2a..7b990e5f0c 100644
--- a/lib/OpenLayers/Layer/TMS.js
+++ b/lib/OpenLayers/Layer/TMS.js
@@ -31,7 +31,11 @@ OpenLayers.Layer.TMS = OpenLayers.Class(OpenLayers.Layer.Grid, {
 
     /**
      * APIProperty: tileOrigin
-     * {<OpenLayers.Pixel>}
+     * {<OpenLayers.LonLat>} Optional origin for aligning the grid of tiles.
+     *     If provided, requests for tiles at all resolutions will be aligned
+     *     with this location (no tiles shall overlap this location).  If
+     *     not provided, the grid of tiles will be aligned with the map's
+     *     <maxExtent>.  Default is ``null``.
      */
     tileOrigin: null,