The NYT’s has created a huge variety of interactive maps based on the Census Bureau’s American Community Survey. Click on “view more maps” to see different breakdowns (income, race, housing, education). Roll-overs popup details at the county or census area level. Related article.

Here’s the percentage of foreign born population in Washington DC:

Change in income level since 2000:

This one shows how racially divided DC still is (green vs blue)”:

They also used the data for some more detailed analysis, such as “How NYC’s Racial Makeup has changed since 2000” (clockwise from upper left: white, hipanic, asian, black). Related article.