MapTech, a creator and seller of mapping software and maps, has a collection of historic USGS topographic sheets, mostly dating from the first half of the 2oth century. Chris Marshall toured around to a number of libraries armed with a scanner and laptop and proceeded to put this digital collection together of topographic maps from the northeastern United States. These maps are beauties and come in approximately 2 MB jpeg files. Users can access the collection via quad or town index and by clicking on a state map. In some locations, maps from more than one date are available.

By way of Here Be Dragons