Los Alamos (Spanish: Los Álamos, meaning "The Cottonwoods" or "The Poplars") is a town in Los Alamos County, New Mexico, United States, that is recognized as the development and creation place of the atomic bomb—the primary objective of the Manhattan Project by Los Alamos National Laboratory during World War II. The town is located on four mesas of the Pajarito Plateau, and has a population of 12,019. It is the county seat and one of two population centers in the county known as census-designated places (CDPs); the other is White Rock.
The ruins of permanent Puebloan settlements, such as those located in nearby Bandelier National Monument and Tsankawi, and numerous other sites such as cliff dwellings indicate that the area has been inhabited during various eras since around 1150 AD. The first settlers on the plateau are thought to be Keres speaking Native Americans around the 10th century. Around 1300, Tewa settlers immigrated from the Four Corners Region and built large cities but were driven out within 50 years by Navajo and Apache raids and by drought.
In the late 19th century, homesteaders utilized the land for ranching. Most homesteaders built simple log cabins that they only lived in during warm weather to feed livestock. Many of the homesteaders later moved down to the warmer Rio Grande Valley. In 1917, homesteader Harold H. Brook sold part of his land and buildings to Ashley Pond II, a businessman from Detroit who founded the Los Alamos Ranch School. The area was used to teach young men basic ranching and other outdoor survival skills.
In 1943, during World War II, the United States Department of War exercised eminent domain over the Ranch School and all remaining homesteads in the area so that the relatively isolated location could be used for the secretive Manhattan Project, which ultimately developed the world's first nuclear weapons.