| Los Alamos County New Mexico Cities/Towns - Los Alamos (County Seat) |
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Your Ad Here Los Alamos County is a county located in the U.S. state of New Mexico. In 2000, its population was 18,343. The seat of the county is at the townsite of Los Alamos. History Founded in 1949. The county is home to the Los Alamos National Laboratory. ![]() |