Photogrammar
The bulk of the photos come from the collection of the Farm Security Administration - Office of War Information.
The U.S. government directed professional photographers to record what was happening across the country in order to build support for New Deal relief programs. Yale University and the Library of Congress have now made them available online: http://photogrammar.yale.edu/
About 90,000 of the photographs are categorized by geographical location and are easily searchable on a map.
I had fun walking down memory lane as I looked at images from South Dakota, where I grew up. I attended a country school through 8th grade. The school pictured here is not mine, but it's just a couple counties away. Country schools - and the terrain - look pretty much the same even if they were 50 miles and 20-30 years away.
Spend a little time looking at Photogrammar and you could see your hometown as it was in the late 1930s! Hey, it's even possible to find family members! For example, among the South Dakota photos were several pictures identified as the L. M. Schulstad family of Aberdeen. There are also many photos of unidentified children and adults tagged as "resident of XX" or "children in XX." The name of the photographer and the month/year accompany each image. If you're looking at photos taken in a small town or rural area, it wouldn't be impossible to figure out who's pictured. The great majority of photographs are considered to be in the public domain; labels on only a few indicate they may be restricted. Thanks to Dick Eastman for alerting us to the existence of this collection.