The nerds team at ProPublica (their choice of words, not mine, in spite of this) has just recovered a nice histogram on income inequality in the 818 largest counties in the U.S. It was originally published in 2011.
A few comments: The search box on top is really helpful, although I miss the Y-axis. It's difficult to estimate how many counties lie on each frequency range. Also, it'd be really interesting to see these compared to the U.S. median and to other countries. In any case, this is great stuff.
|Income inequality in the 818 largest counties in the U.S. ProPublica.|