
Los Alamos County
- State:
- New Mexico
Los Alamos County's estimated 2025 population is 19,786 with a growth rate of 0.87% in the past year according to the most recent United States census data. Los Alamos County is the 19th largest county in New Mexico. The 2010 population was 17,995 and has seen a growth of 9.95% since that time.