Archives of HOLC Residential Security Maps

Here's a veritable goldmine: an archive of 35 scanned RESIDENTIAL SECURITY MAPS, courtesy of Urban Oasis. Check out Flint's map, which reverses a familiar pattern by having blue in the center and lots of red at the periphery. Oakland's is also interesting for the stark north / south divide. But really, we're just getting started analyzing these.  

Here is another archive of 14 maps from 14 cities in Ohio, courtesy of the Ohio State University Library.