Ever since those years I worked at the US Geological Survey, I have been hoping that the thousands of USGS historical topographic maps would someday be easily accessible for the geospatial data user. These maps, representing an enormous investment in documenting the landscape at great detail, were compiled over nearly a 100 year period. TopoView has just been launched that provides this type of service: http://ngmdb.usgs.gov/maps/TopoView/.
TopoView is intended to serve the immediate need for the older printed topographic maps to become easily searched, viewed, and downloaded. The approximately 163,000 maps at different scales including 1:24,000, 1:48,000, 1:63,360, 1:100,000, 1:250,000, and a few others, available through this interface were scanned by the USGS Historical Topographic Mapping Collection project. They are provided in GeoPDF and in JPG formats. Users can use the map index interface to access a chosen location, and then browse all of the maps, scales, and formats available for that location.
Currently, the interface is best for viewing and downloading one map at a time, and the Flash interface may hinder users working on the Mac platform. This index does not include all historical USGS maps. I would like to see these maps in formats that are easier for the GIS community to use. I also would like to see all of these maps offered as a seamless service in ArcGIS Online.
Nevertheless, I recognize that this is only the first draft of this interface and it still represents a huge leap forward. It is a wonderful resource for comparing past to present agricultural and urban land use changes, coastal processes, changes in glaciers, the movement of and channelization of rivers, and so much more.