I finally got round to attacking the problem of too many markers loading on the map area at once. This would have been a very tricky one, since there are a few options available. In the end I found a great clustering object written by Jef Poskanzer on the Google Map API group. Here's a link to his post with contains a reference to the javascript file: http://groups.google.com/group/Google-Maps-API/browse_thread/thread/745270c3865679d7/8dd92e3d9cf556f5?q=clusterer&rnum=1#8dd92e3d9cf556f5 I had to adapt it a little for my use, but it's more or less plug and play. Now any external data with a lot of markers won't load them all at once, but will react to the users input.