The Brookings Institution recently released an interactive chart that compares household income distribution in 575 cities in the US.
Two patterns have emerged from the data set. Firstly, smaller cities look more like the nation than larger cities. Smaller cities in the US mirror the national income distribution almost exactly, whereas low-income and very high-income households are overrepresented in large cities.
Secondly, it seems that regional differences factor into income inequality. Many of the expansive Southern and Western cities have more middle-income neighbourhoods and households, while deeper levels of inequality and segregation can be found in cities and metro areas in the Midwest and Northeast.
Further details here.