Aerial photography archives

Notes on where to find historical aerial imagery (thanks to Kass Green): The USDA has an archive of aerial imagery in Salt Lake City at APFO  There is a ArcGIS online map of the  tiles and dates of this photos. Search in ArcGIS online for the AFPO Historical Availability Tile Layer. USDA is in the process of scanning these photos, but you can order them through a manual process now (which can take a long time). 

The EROS data center in Sioux Falls also has an archive of high altitude photos for the US from the 1980s.  Also check out  and .  These photos are available digitally, but are not terrain corrected or georeferenced.