DISTRICT 2010 POPU. 2017 POPU. CHANGE REP. TX-22 698,504 897,080 198,576 Olson (R) TX-26 698,488 879,237 180,749 Burgess (R) FL-09 696,344 868,945 172,601 Soto (D) TX-03 698,488 870,763 172,275 Johnson (R) TX-08 698,488 863,498 165,010 Brady (R) TX-31 698,487 853,799 155,312 Carter (R) TX-10 698,487 846,261 147,774 McCaul (R) FL-10 696,345 830,014 133,669 Demings (D) TX-35 698,488 830,041 131,553 Doggett (D) NV-03 675,138 803,545 128,407 Rosen (D)

As you can see, much of the nation’s growth is concentrated in Texas, with 7 of the top 10 CDs from the Lone Star State; more specifically, in the suburbs of Houston (TX-22 and TX-08), Dallas (TX-26 and TX-03), Austin (TX-31 and TX-35), or in an absurd monstrosity that includes suburbs of both Houston and Austin (TX-10). Six of these seven Texas districts are represented by Republicans as well, though the 31st, where Democratic candidate M.J. Hegar is challenging GOP incumbent John Carter, has become a competitive race.

Unfortunately, this indicates that Texas—which is poised to gain at least two seats in reapportionment after 2020; see the map above by my colleague Stephen Wolf—will be gaining one and possibly more Republican seats in its suburbs, as excess population from these red districts will likely be spun off and combined into new districts. It’s worth noting, though, that even in these mostly conservative suburbs, the bulk of the growth is coming among people of color. TX-22, mostly in diverse and well-educated Fort Bend County, is very much a case in point: of the nearly 200,000 people that it gained in the last seven years, around 46,000 are white, while 58,000 are Hispanic, 31,000 are African American, and the plurality of the gains (61,000) are Asian.

(Of course, keep in mind that these numbers include every person. If you drill down into only the citizen voting-age population, the gains are likely to be proportionately much more white; many of these new residents aren’t able to vote because they aren’t citizens, are too young, or both. That, right there, sums up why Texas tends to remain out of Democrats’ reach despite being very diverse, but also why it moves slightly closer to being within our grasp every cycle.)

The other three in the top 10 are Democratic-held seats in the fast-growing Orlando and Las Vegas areas. Florida is likely to gain two more seats in reapportionment, and one of those seats is likely to end up in central Florida, where the state is growing the fastest and where a lot of the growth is among the Puerto Rican population. Nevada, however, isn’t likely to gain another seat after 2020, meaning NV-01 is just likely to expand into the suburbs to absorb some of the 3rd’s excess population.

One other interesting CD that narrowly misses the cut for the top 10 is also one of the most competitive races this year (in fact, maybe not that competitive, and instead more like one of the Democrats’ likeliest pickups): Virginia’s 10th district in Washington’s suburbs, currently held by Republican Barbara Comstock, and which gained 123,000 residents in seven years. The majority of that growth in the 10th has been the expansion of its Asian and Hispanic populations (+36,000 and +46,000 respectively, compared with only 15,000 new white residents). Following 2020, the 10th may wind up being whittled down to a pretty solidly Democratic district, with its more exurban reaches cut off and added to the nearby 1st or 7th (though adding more swingy NoVa suburbs to those more difficult districts might help push them in a more Democratic direction, too).

Now let’s turn to the districts that have lost the most overall population:

DISTRICT 2010 POPU. 2017 POPU. CHANGE REP. OH-11 721,032 675,475 - 45,557 Fudge (D) MS-02 741,862 701,238 - 40,624 Thompson (D) WV-03 616,141 582,846 - 33,295 Jenkins (R) MI-13 705,974 674,157 - 31,817 Vacant (was D) MI-05 705,975 677,788 - 28,187 Kildee (D)

Three of the five districts are among the CDs with the highest African American percentages: Ohio’s 11th in Cleveland, Mississippi’s 2nd in the rural Delta, and Michigan’s 13th in Detroit. Michigan’s 5th contains the city of Flint—certainly a place that people aren’t very eager to move to right now—but it has a sizable white majority, overall, and most of the population decline was among its white population. (Michigan is likely to lose one more seat in reapportionment after 2020, with the lost seat likely to come from Detroit, or possibly from the suburbs in between Detroit and Flint.)

The other one of the five with the largest loss is West Virginia’s 3rd district, in the state’s rural south; it’s the only Republican-held seat of the five, though it’s definitely a potential pickup in 2018 with Democratic state Sen. Richard Ojeda a strong contender here. Whoever wins the 3rd may well only enjoy a short-term stay in it, though, because West Virginia is almost certain to be reduced to only two House seats after 2020 (as you can see from the very low number that its CDs even started with, in 2010).

Now let’s turn to changes within congressional districts’ populations for particular races or ethnicities. As I said earlier, the ACS isn’t limited to just total population; it includes a mountain of race, age, education, occupation, and housing data. From here out, I’ll switch to using percentage change as the basis for ranking, rather than changes in the raw numbers (because, unlike with total population, different districts’ populations of a particular race often start from very different baselines from one another).

DISTRICT 2010 HISPANIC POP. % OF TOTAL 2017 HISPANIC POP. % OF TOTAL CHANGe REP. CA-08 248,397 35.3 310,386 43.0 + 7.7 Cook (R) FL-09 242,006 34.8 365,228 42.0 + 7.3 Soto (D) CA-41 392,952 55.9 481,075 62.8 + 6.9 Takano (D) TX-11 232,747 33.3 297,228 39.1 + 5.8 Conaway (R) TX-18 270,439 38.7 352,900 44.1 + 5.4 Jackson Lee (D)

The biggest gainer among Hispanics, percentage-wise, is California’s 8th district, a sprawling district that covers much of the empty desert part of southern California, but with most of its population in one small corner, in the exurbs of the Inland Empire. The 8th is a district that, while still reddish, is one that’s been moving in the Democratic direction—but, unfortunately, there’s no chance of a Democratic pickup here in 2018, as the vagaries of California’s top 2 primary left us with two GOP general election candidates.

Interestingly, the 8th’s overall population didn’t change that much; it gained only around 20,000 residents, but it gained over 60,000 Hispanic residents while losing 40,000 white residents, presumably migration to elsewhere. By contrast, Florida’s 9th district had by far the largest numeric gain of Hispanics of any district (over 120,000)—largely thanks to migration from Puerto Ricans, who tend to be clustered in the Orlando area, rather than the Cuban-dominated Miami area. But it also gained a lot of everybody (it’s #3 on the list of overall gainers), so it didn't wind up with as large a percent change as in CA-08.

California’s 41st district, in third place, is centered on Riverside and is a nearby neighbor to the 8th. The Texas districts that follow it are quite the study in contrasts: the 11th, the emptiness around Midland/Odessa in West Texas, is one of the reddest districts in the entire country, and given how conservative the white population here is, and different turnout rates between its white and Hispanic populations, may still wind up being dark red even if it soon becomes Hispanic-majority. The 18th, however, is in downtown Houston, and until recently was the Houston area’s black-plurality district. In the last few years, thanks to surging Hispanic growth and a flat African American population, it became Houston’s third Latino-plurality district instead.

Only a small handful of CDs saw the Hispanic percentage of their population decline. The biggest drop, surprisingly, was in the Austin-to-San Antonio-area TX-35, where the Hispanic population still grew robustly (+60,000 more), but where the white population grew rapidly too, pushing the Hispanic percentage down a bit from 63 percent to 60 percent. It’s followed by two districts where there was a more predictable pattern, where the overall population stayed mostly the same but where the number of Latino residents actually fell as they were replaced by white gentrifiers, in Chicago’s IL-04 and Brooklyn’s NY-07.

In fact, that’s a good transition point to the districts where the white percentage grew the most (although neither IL-04 nor NY-07 appears in the top 5):

DISTRICT 2010 WHITE POP. % OF TOTAL 2017 WHITE POP. % OF TOTAL CHANGE REP. IL-07 188,031 26.4 213,844 30.7 + 4.3 Davis (D) NY-09 213,133 29.7 252,215 33.6 + 3.9 Clarke (D) NY-13 87,781 12.2 114,930 14.3 + 2.1 Espaillat (D) PA-02 201,657 28.6 222,346 30.6 + 2.0 Evans (D) CA-34 64,930 9.2 85,010 11.1 + 1.9 Gomez (D)

These, as well, are all urban districts where there’s a lot of gentrification and financial inequality going on, though in three of the five, they’re mostly-African American districts: Illinois’s 7th district (which is mostly on Chicago’s West Side, but also includes the Loop), New York’s 9th (in the close-in parts of Brooklyn), and Pennsylvania’s 2nd (the western half of Philadephia—keep in mind that the 2017 Census data on CDs covers the current districts, not the new ones that will take effect next year in Pennsylvania). The list is rounded out with New York’s 13th (in Harlem and Washington Heights), and California’s 34th (in downtown Los Angeles).

One district you might expect to see there that isn’t there is New York’s 14th, where there was a lot of speculation that increased participation by white hipsters helped Alexandria Ocasio-Cortez knock off long-timer Joe Crowley in the Democratic primary. While that may still be true, the white percentage of the population in the 14th kept going down during that period. Interestingly, though, the Hispanic percentage in the district declined a small amount as well; to the extent that any group grew in the 14th this decade (the district has lost population as a whole), the growth was only among Asians.

You get a very different impression if you look at CDs where the white population grew the most in terms of raw numbers, rather than percentage change. Leading the way is South Carolina’s 1st district, which gained over 86,000 new white residents; the district is centered on Charleston, but includes a number of retirement destinations as well like Hilton Head Island. Following behind in second place is Texas’s 26th in the Dallas suburbs, which was near the top of the list of total gains as well. (Less than half of TX-26’s new residents are white, but the overall growth numbers are still huge.)

Instead of looking at the districts that gained the most whites, though, the more interesting question may be which districts lost the biggest share of white residents:

DISTRICT 2010 WHITE POP. % OF TOTAL 2017 WHITE POP. % OF TOTAL CHANGE REP. FL-23 340,721 48.9 298,875 39.6 - 9.3 Wasserman Schultz (D) FL-09 339,205 48.7 352,661 40.6 - 8.1 Soto (D) VA-10 484,393 66.6 499,228 58.7 - 7.9 Comstock (R) TX-24 373,234 53.4 364,935 45.6 - 7.8 Marchant (R) NV-01 245,552 36.4 206,938 28.7 - 7.7 Titus (D)

At the top of the list is Florida’s 23rd in Miami’s suburbs, where the white share of the population fell from 49 percent to 40 percent. You might expect this was mostly due to replacement by new Latino residents, as more affluent Cubans and Colombians move to the ‘burbs, but the Hispanic percentage in FL-23 only went up from 33 to 38 percent, so that accounts for only part of the change. There was also a significant African American influx into the district (probably mostly Haitian) making up most of the rest. Could Debbie Wasserman Schultz fall victim to a similar demographics-driven primary challenge as befell Joe Crowley? It’s not clear who’d mount that challenge, but it’s definitely something to keep an eye out for.

And right below her is a data point that should be flashing red alerts at NRCC headquarters, if it already wasn’t: the aforementioned Virginia’s 10th district, where Barbara Comstock’s constituency got much less white. The 10th did gain white residents, but it gained a ton of new residents, the vast majority of whom aren’t white. And below that is a perpetually intriguing district, Texas’s 24th, a swath of middle-class suburbs between Dallas and Ft. Worth, held by unmemorable GOP backbencher Kenny Marchant. Unlike a number of other Texas suburbs, which gained white residents but also a lot of everyone else, the 24th actually lost white residents during the decade. All prognosticators have TX-24 as Safe Republican this year, but it could potentially become more interesting in coming cycles.

Now let’s look at the districts with the largest African American gains:

DISTRICT 2010 BLACK POP. % OF TOTAL 2017 BLACK POP. % OF TOTAL CHANGE REP. GA-13 377,021 54.5 448,172 59.6 + 5.1 Scott (D) MI-09 70,499 10.0 102,437 14.2 + 4.2 Levin (D) TX-06 124,479 17.8 167,437 21.1 + 3.3 Barton (R) TX-07 77,844 11.1 112,943 14.1 + 3.0 Culberson (R) FL-21 94,213 13.5 129,210 16.4 + 2.9 Frankel (D)

In each case, these are middle-class (or even rather affluent, in the case of TX-07) suburban districts, not the downtown districts you might be picturing. At the top is Georgia’s 13th district, in Atlanta’s southern suburbs. (While Atlanta proper gets its own black-majority CD, it also has two black-majority CDs in its suburbs, with more of the growth being concentrated in the 13th. The 13th also had the largest numeric gain in African American residents of all CDs.) Michigan’s 9th district is in the suburbs of Detroit, and as many African American families move out of the city, they’re staying in the Detroit area, just to the other side of the once-impermeable cultural boundary of 8 Mile Road.

There are two Texas suburban districts here, one of which, the Houston-area 7th, may well be the best chance for a Democratic pickup of any Texas House seat this year (where Lizzie Fletcher is challenging incumbent John Culberson ... though the competitiveness here may be because of strong Never-Trump sentiments in a well-educated electorate, and Culberson phoning it in, more so than any demographic changes). The 6th, a currently open seat in the suburbs south of Fort Worth, is Safe Republican on most prognosticator’s depth charts this year, but is one of those districts that might get put into play with a few more years of demographic change. And rounding out the list is Florida’s 21st district, a solidly Democratic district in Palm Beach County. (Just don’t tell the district’s most famous part-time resident, who lives at Mar-a-Lago, about his new neighbors. Sad!)

Finally, let’s take a look at the districts with the biggest increase in Asian residents:

DISTRICT 2010 ASIAN POP. % OF TOTAL 2017 ASIAN POP. % OF TOTAL CHANGE REP. CA-15 189,612 27.0 272,987 34.8 + 7.8 Swalwell (D) CA-17 345,845 49.2 425,657 55.2 + 6.0 Khanna (D) CA-18 131,576 18.7 178,477 24.0 + 5.3 Eshoo (D) CA-45 145,371 20.7 197,705 25.4 + 4.7 Walters (R) CA-32 105,354 15.0 141,695 19.5 + 4.6 Napolitano (D)

You may be surprised at the large increases in this category, but Asians have recently surpassed Hispanics as the nation’s fastest-growing race or ethnicity. California, especially the Bay Area, dominates this category. (The 6th and 7th slots on the list, however, are both in New York City, though, maybe surprisingly, neither of them is the Flushing-area 6th district. Instead, it’s NY-11, mostly on Staten Island, and NY-05, a black-majority CD in southeast Queens but one with a rapidly growing South Asian population.)

Maybe the most notable of these five, for purposes of the 2018 election, is California’s 45th district in Orange County. (The other four are very safely Democratic.) It’s currently represented by Republican Mimi Walters, though if the recent polls are to be believed, she’s about to be replaced by Democrat Katie Porter. While Orange County residents of all races seem very interested in fleeing their traditional home in the Republican Party, the huge growth in Asian residents in and around Irvine in the last decade may be hastening Walters’ possible departure.