[5][6][7] The ruins of 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.

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 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.

Los Alamos was referred to under the code name "Site Y" by military personnel, and was known only as "The Hill" by many in nearby Santa Fe.

All employees recruited to work at the Los Alamos site were given a memorandum instructing them to travel to Santa Fe and report to the U.S. Army Corps of Engineers office at 109 East Palace Avenue.

[11] The project was further concealed by designating its mailing address as PO Box 1663, Santa Fe, N.M.[12] All incoming truckloads were falsely labeled as common items in order to conceal the true nature of their contents, and any outbound correspondence by those working and living in Los Alamos was censored by military officials.

In 1957, the AEC pulled back the security perimeter to the laboratory itself and opened up the town for visits by the general public.

[15] Since the town's appearance had changed drastically since the 1940s, the filmmakers arranged for the construction of a set based on 1940s-era Los Alamos at Ghost Ranch and filmed exterior scenes at that location.

[15] Los Alamos is located in northern New Mexico between the Rio Grande and the eastern rim of the Valles Caldera on the Pajarito Plateau, approximately 35 mi (56 km) to the northwest of Santa Fe.

The Los Alamos Townsite and White Rock are located on flat mesa tops separated by steep canyons, known as potreros.

Los Alamos' geographical location causes its wildlife and vegetation to be diverse compared to surrounding areas in the state.

[20] Black bears (brown-color variation), elk, mule deer, bobcats, gray foxes, skunks and chipmunks are examples of mammals living in the area.

[22] Among these are broad-tailed hummingbirds, hairy woodpeckers, zone-tailed hawks, common ravens, western bluebirds, and great horned owls.

[22] Wildfires have affected the county, but the most destructive to the townsite was the Cerro Grande Fire of May 2000, which caused an estimated $1 billion in damages and destroyed more than 400 homes.

The Federal Emergency Management Agency (FEMA) built temporary housing on North Mesa for those who were displaced by the fire.

Though there was no loss of life, other effects include damage to LANL facilities (nuclear material was not affected), flash-flooding, and erosion.

The county maintains New Mexico's only refrigerated, NHL regulation, outdoor ice skating rink on the sun-shaded floor of Los Alamos Canyon, almost beneath the Omega Bridge.

Los Alamos is host to several sporting events: On November 10, 2015, the National Park Service and the U.S. Department of Energy announced the establishment of Manhattan Project National Historical Park in Los Alamos, along with units in Hanford, Washington and Oak Ridge, Tennessee.

Los Alamos is the fifth-fastest-growing city in New Mexico, after Albuquerque, Rio Rancho, Las Cruces, and Ruidoso.

Approximately 40% of the laboratory's employees live in Los Alamos, while the remainder commute from Santa Fe, Española, Taos, and Albuquerque.

About 66% of the people who work in the national laboratories commute daily to the lab; some take the Atomic City Transit, Rail Runner Express, use the Park and Ride, or carpool with other employees.

NM 502 sees significantly more traffic because it connects with US 84/285, which delivers access to several Pueblo communities between Española and Santa Fe.

The hospital provides "complete medical, surgical, obstetrical, pediatric, emergency, and diagnostic services"[67] and employs about 300 Northern New Mexicans.

A non-profit organization called Cold War Patriots provides these individuals and their families with information about the healthcare benefits available to them.

[69] The radio telescope located in Los Alamos is one of ten dishes composing the Very Long Baseline Array (VLBA).