In Alexandria Ocasio-Cortez’s congressional district, which includes part of the Bronx and Queens, 68% of adults speak other than English at home. 46% of the population is foreign-born (compared to 13% nationwide).
In 39 U.S. counties, a majority of adult citizens speak any language other than English at home. Most of these counties lie along the southwestern edge of Texas, but the largest of them are Bronx County in New York (1.3 million people with more than 53 percent of adult citizens not speaking English) and Miami-Dade County in Florida (2.5 million people with more than two-thirds of adult citizens not speaking English at home) (from here).
On a state rather than county basis, in three states there are at least 25% of the total population which speaks Spanish at home: Texas (30%), California (29%) and New Mexico (28%). For the U,S. as a whole, 13% of the population speaks Spanish at home.