Donald J. Trump’s biggest gains were along the Texas border, a Democratic stronghold where most voters are Hispanic. He won 12 of the region’s 14 counties, up from five in 2016.

The former president captured 55% of Latino voters in the state, according to exit polls. He also won 14 out of the 18 counties within 20 miles of the border, a number that doubled his 2020 performance in the Latino-majority region.

Trump soundly defeated Harris in 12 of 14 Texas counties touching the border. Concerns over immigration only partly explain it.