The National Geospatial Program today launches the USGS Historical Topographic Map Collection (see FAQ, PR).
It offers more than 90,000 of the 200,000+ USGS historical topo maps - some dating back to the Agency's founding more than 126 years ago. The maps are georeferenced and can be downloaded for free from the USGS Store. Since they are in a GeoPDF format, no special programs are required, and they can be used in conjunction with the US Topo maps. (Well, except on a Mac for which the TerraGo plug-in is not available!)e website includes advanced search functions, status graphics (more maps are in the works via a quick turnaround process) and download instructions.
- via USGS PR