Los Alamos is a census-designated place in Los Alamos County, New Mexico, United States, that is recognized as one of the development and creation places of the atomic bomb—the primary objective of the Manhattan Project by Los Alamos National Laboratory during World War II. The town is on four mesas of the Pajarito Plateau, and had a population of about 13,200 as of 2020. It is the county seat and one of two population centers in Los Alamos County; the other is White Rock.