A U.S. map of English as a second language

"More than a quarter of counties in the United States have at least one in 10 households where English is not the language spoken at home. Spanish is, by far, the most common language other than English spoken in the home, especially on the West Coast, in the Southwest, the Eastern urban corridor and other big cities. Native American languages are also common in the West, as is French around New Orleans and in some counties in the Northeast. German is a common language in some Midwestern and Western areas." 

A larger, interactive map, where you can click for information on your county, is at the Washington Post.