Los Alamos, CA has a population of 1,351 and is the 13,313th largest city in the United States. The population density is 349 per sq mi which is 50% higher than the California average and 286% higher than the national average. The median age in Los Alamos is 35 which is approximately 3% lower than the California average of 36. In Los Alamos, 54% of the population over 15 years of age are married, 70% speak English and 24% speak Spanish. 68% of Los Alamos residents were born in California, 13% were born out of state, 0% were born outside of the United States and 19% were foreign born.