The Most District: Which district has the most U.S.-born residents? Kentucky's 5th
Despite being centrally located between a number of major metropolitan areas, eastern Kentucky—the part of the state covered by the sprawling 5th congressional district—is, functionally, a pretty isolated part of the nation, without major cities, navigable rivers, and mostly without even interstate highways. It’s located in the Appalachian uplands, a plateau that’s nearly 500 million years old, thrust up by colliding plates and then scoured by glaciers as well as gradual erosion by streams. What’s left is a maze of ridgelines and valleys, usually running parallel to each other but often snaking around in squiggles or loops. The Appalachians were, in the country’s early years, a major barrier to east-west travel, and even today are more of a place that you go around, not through.
The lack of large, flat areas of farmable land and the lack of transportation infrastructure (which limited the development of heavy industry, which in turn discouraged the development of larger cities) meant there was never much of a population boom here. Some Eastern and Southern European immigrants did move to the parts of Appalachia where there were large coal-mining operations, but for the most part, the residents of Appalachia were the descendants of the original Scots-Irish settlers there during colonial times (who couldn’t afford to purchase enough land to farm successfully in the southern lowlands, and many of whom preferred the relative solitude of the hills anyway). And today, with the coal-mining sector having mostly dried up, and with not much else in the area’s small towns beyond service sector jobs, there isn’t much impetus left for migration there.
And that leaves Kentucky’s 5th as the congressional district with the highest percentage of people who were born in the United States: 99.1 percent. (0.7 percent of its population is foreign-born, and 0.2 percent was born in Puerto Rico, U.S. island areas, or abroad to American parents.) That also means that, without much in-migration, and with deaths outstripping births, Kentucky’s 5th is one of the few congressional districts in the country that lost population between 2010 and 2017 (losing nearly 27,000 residents).