In July, we posted that the USGS was releasing more than 200,000 historical maps from to 1884 to 2006) online.
Today the USGS announced that more than 90,000 hi-res digitized maps are available for download (free; GeoPDF) or as a scanned print (fee-based, $15/maps).
Historical maps are an important national resource as they provide the long-term record and documentation of the natural, physical and cultural landscape. The history documented by this collection and the analysis of distribution and spatial patterns is invaluable throughout the sciences and non-science disciplines. Genealogists, historians, anthropologists, archeologists and others use this collection for research as well as for a framework on which a myriad of information can be presented in relation to the landscape. For more than 130 years, the USGS topographic mapping program has accurately portrayed the complex geography of our nation through maps using the lithographic printing process. The historical collection contains high resolution scanned images from the USGS legacy series and other sources.
See Also: US Topo, Next Gen Maps