It’s hard to believe eugenics was as popular here as it in fact was without seeing the visual evidence. The images here include Fitter Family contests, where white Americans competed at state fairs–much like cattle–to determine who had the best breeding. (Make sure to check out this traveling exhibit.) Also, lots of documents and flyers linking criminality to immigrants and heredity. (Oh, the irony of using the swastika to indicate the racial inferiority of Germans!) The interface is pretty clunky but it’s worth pecking around.
For background on the early 20th century American eugenics movement, you could do worse than [Carrie’s] interview with historian Daniel Kevles.