Donald Trump ran for president on a promise to crack down on illegal immigration. But most of the people who are in the U.S. illegally live in places that voted for his opponent, Hillary Clinton.

More than 2 million of the nation’s roughly 11 million undocumented immigrants live in just two metropolitan areas, New York and Los Angeles, according to a new analysis of 2014 Census Bureau data from the Pew Research Center. Voters in both cities supported Clinton by overwhelming margins. Most of the remaining 9 million undocumented immigrants are concentrated in large urban areas that likewise voted for Clinton over Trump. (Overall, Clinton won 17 of the top 20 metro areas for undocumented immigrants, by an average of more than 20 percentage points.)

UNDOCUMENTED IMMIGRANT POP. METRO AREA TOTAL SHARE OF POP. CLINTON 2016 VOTE MARGIN (PPT) New York (NY-NJ-PA) 1,150,000 5.7% +26.9 Los Angeles (CA) 1,000,000 7.5 +36.2 Houston (TX) 575,000 8.7 -1.0 Dallas-Fort Worth (TX) 475,000 6.9 -7.2 Miami-Fort Lauderdale (FL) 450,000 7.3 +27.6 Chicago (IL-IN-WI) 425,000 4.5 +32.3 Washington (DC-VA-MD-WV) 400,000 6.8 +42.4 Atlanta (GA) 250,000 4.5 +7.5 Riverside-San Bernardino (CA) 250,000 5.6 +6.9 Phoenix (AZ) 250,000 5.5 -4.6 San Francisco-Oakland (CA) 240,000 5.3 +60.8 Boston (MA-NH) 180,000 3.7 +31.9 San Diego (CA) 170,000 5.3 +17.9 Las Vegas (NV) 170,000 8.0 +10.6 Philadelphia (PA-NJ-DE-MD) 160,000 2.6 +27.4 Seattle (WA) 150,000 3.9 +34.7 Denver (CO) 130,000 4.7 +13.2 San Jose-Sunnyvale (CA) 120,000 6.5 +51.6 Orlando (FL) 110,000 4.6 +11.7 Austin (TX) 100,000 5.0 +19.6 Top 20 metro areas by undocumented immigrant population, 2014 Sources: Pew Research Center, Dave Leip’s Atlas of U.S. Presidential Elections

The Pew analysis, its first to offer estimates of the undocumented population at the local level, shows that undocumented immigrants are significantly more concentrated than the U.S. population overall. About 61 percent of undocumented immigrants live in 20 metro areas; those same areas account for just 36 percent of the U.S. population.

Unsurprisingly, undocumented immigrants tend to live in large, diverse urban areas with large immigrant populations. After New York and LA, the areas with the biggest undocumented populations were Houston, Dallas, Miami and Chicago. But undocumented immigrants aren’t necessarily city-dwellers: In most metro areas for which estimates were available, a majority of undocumented immigrants lived in the suburbs or outlying cities, not in the largest city.

Despite the focus on illegal immigration during last year’s presidential campaign, the total number of undocumented immigrants living in the U.S. has fallen by about a million from its 2007 peak. (The decline has been especially steep among immigrants from Mexico.) Nor are undocumented immigrants moving to new parts of the country in large numbers: The list of the top 20 metro areas for undocumented immigrants has been relatively unchanged for a decade.

Still, the Pew report shows that there are undocumented immigrants in virtually every corner of the country. Pew estimates there are about 20,000 undocumented immigrants in Boise, Idaho, for example, and perhaps 5,000 in and around Buffalo, New York.

Pew’s estimates are based on an approach that it and other researchers have used in the past: First they take the total number of foreign-born residents in a given area, a figure derived from the Census Bureau’s annual American Community Survey. Then they use data from the Department of Homeland Security and other sources to estimate the number of immigrants who are in the area legally. The difference between the two numbers is the number of undocumented immigrants.

The approach isn’t perfect. The American Community Survey tries to count the total population, regardless of immigration status. But undocumented immigrants are often reluctant to speak to government survey-takers, which means they are probably undercounted. Researchers try to adjust for this “undercount,” but the estimates nonetheless carry significant margins of error.