But while we know there is income inequality across the party’s districts, is there also inequality within the party’s districts?

Thanks to the U.S. Census Bureau’s tabulation of the Gini indices for each congressional district, we can answer that question. Here is what the distribution looks like:

(Full data are at the bottom of this post.)

As the data show, Democrats have a lock not only on the country’s richest districts but also on the districts with the highest in-district income inequality.

Democratic Representatives Carolyn Maloney (N.Y.-12) and Chaka Fattah (Pa.-02) illustrate the distinction between the richest and the most unequal districts.

Maloney’s seat topped the AP’s list of wealthiest districts. Per-capita income in the New York 12th comes out to $75,479, or “more than $75,000 a year for every man, woman and child,” as the AP put it. The median household income in Maloney’s district, meanwhile, is a cool $82,823 (21st of all the districts), but it doesn’t compare to the mean household income, which is $142,577 (first of all the districts). In other words, there are a small number of super-rich people in Maloney’s district pulling up the household average. And that’s what the Gini index reports, too: Her district has the third-highest income inequality, which is understandable, since it doesn’t just include the Manhattan’s Upper East Side, but also less tony neighborhoods like Queens’s Long Island City and Brooklyn’s Greenpoint.

Fattah, on the other hand, doesn’t come close to showing up on the list of rich districts—per-capita income in his district is $25,564, just over a third of what it is in Maloney’s. Again, however, there’s a sizable gap between the median household income ($34,897) and the mean household income ($61,718)—which reflects the fact that Fattah doesn’t just represent economically depressed West Philadelphia but also affluent neighborhoods like Chestnut Hill that are right next door. Fattah’s district is even more vertiginously unequal than Maloney’s—it’s the second most unequal in the nation. (First place goes to Representative Jerrold Nadler from the N.Y.-10, which includes both Manhattan’s Upper West Side, and neighborhoods in Brooklyn like Red Hook, Bensonhurst, and Borough Park. Minority Leader Nancy Pelosi’s San Francisco district is the 16th most unequal.)

Both Maloney’s and Fattah’s districts are deep blue (the Cook Partisan Voting Index for each is greater than D+25), and both reflect two intertwined trends: cities have become, in general, strongholds of the Democratic Party, and cities have become, in general, hives of the most dramatic income inequality in the country.

Considered alongside these well-established trends, the fact that Democrats represent districts that are (on average) more unequal than Republican districts suggests that the parties may have such divergent views on income inequality in part because their members (and constituents) have divergent experiences of income inequality. Could polarization, in other words, be driven by the availability heuristic?