02 June 2014
A superb online map resource
The topographic maps of the U. S. Geologic Service are available online, and as far as I can see, all of them are now free to download. This includes historic maps, going back at least to the 1950s - a great resource for those interested in the history of their community (the embed above is a screencap from a map of Madison, Wisconsin in 1959).
Just go to this link - USGS Store - navigate to your desired location, switch to "mark points" to add a marker, then click on the marker to bring up a pull-down list of available maps.