Los Alamos is a census-designated place (CDP) 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 Vandenburg AFB, Lompoc, Buellton and other Santa Barbara County cities. The population was 1,890 at the 2010 census, up from 1,372 at the 2000 census.