David Rumsey maps and Google maps

I just found out that David Rumsey has taken 120 of his thousands of maps, digitized them and they can be used to lay over Google maps to see the difference in changes over time. These maps cover the time period 1680 to 1930.

This is a neat tool for looking at how things have changed, especially useful for genealogy.

http://rumsey.geogarage.com/gmaps.html