Los Alamos is a census-designated place in Santa Barbara County, California, United States. Although located in the Los Alamos Valley, the town of Los Alamos is usually considered to be a part of the Santa Ynez Valley community. Los Alamos is also connected to other cities Vandenberg AFB, Lompoc, Buellton, Solvang, and other Santa Barbara County cities. It is 140 miles northwest of Los Angeles and 281 miles south of San Francisco. The population was 1,890 at the 2010 census, up from 1,372 at the 2000 census.