I have shown this to a few people before but its to good to not make a note of it. Congress starting giving photographers grant since the mid 1800's. At the time they felt American life should be documented and decided to use photography as a way to document it. The product is sitting in the library of congress where they, no doubt, have been neglected until now. From what i understand the flickr account only holds about 4000 images, and the library has a collection of 14 million. I have been looking threw their immense collection on flickr over the past few months, i pass the findings on, happy hunting.
www.flickr.com/photos/library_of_congress
