Los Alamos - Site Selection

Site Description:

Los Alamos, NM is located in a sparsely populated rural area on the eastern slope of the Jemez Mountains (part of the Rocky Mountain System), in Sandoval County in north central New Mexico. Approximately two-thirds of the Project reservation occupied relatively flat, east-sloping bench land, ranging from 6,900 feet to 8,200 feet above mean sea level, and lying between the valley of the Rio Grande and the east slope of the Jemez Mountain Range. The western third included the rising east slopes of the Jemez Mountains up to 9,200 feet above mean sea level. The entire area was frequently dissected by east-flowing drainage, and the streams had cut innumerable canyons, 100 to 500 feet deep, separated by mesas of varying extent. The canyon bottoms were generally very narrow and rimmed by precipitous cliffs, 100 to 200 feet high. Many of the canyons were box canyons with no access to the mesa on either side.

The project site was located 20 air miles northwest of the state capital, Santa Fe. Santa Fe was also the nearest railhead for the Project and the terminus of a branch line of the Atchison, Topeka, and Santa Fe Railway System which joined the main line at Lamy, 18 miles farther south.

Access to the Project was over two alternate routes extending westward from paved, primary highway 285 that ran northwestward from Santa Fe through Espanola. The shorter route was highway 4 which left the primary highway at Pojoaque and crossed the Rio Grande River at the Otowi Bridge (see Photo). This was a secondary, unsurfaced road along an unimproved alignment from Pojoaque to the junction of State Roads 4 and 5, approximately 1 mile west of Otowi Bridge. This part of the road was 16 to 20 feet wide. In some places the right of way was limited by community buildings located along the highway. Unusually heavy or long vehicles could not use this road because of the weight limitation of the Otowi Bridge, a single-lane suspension bridge of 250 foot span, 10 feet wide, and designed for 10-ton maximum loading, with its east approach in a narrow side-hill cut requiring an approximate 90 degree turn onto the bridge. Also, the route was so rough and curved as to cause damage to vehicles if regularly traveled. The distance from the Plaza in Santa Fe to the Technical Area at Los Alamos via this shorter route was about 35 miles. During heavy rains this road was closed to traffic by two unstabilized stream crossings, so a longer alternate route via State Road 5 and Espanola had to be used. Throughout 1943, the public access roads to the Project were improved by the New Mexico Highway Dept. and resurfaced with asphalt in the summer of 1944.

Two properties , the Los Alamos Ranch School and the Anchor Ranch, had structures usable for housing and storage. The school comprised 54 buildings: 27 houses, dormitories, and living quarters totaling 46,626 sq. ft., and 27 miscellaneous buildings: a public school, an arts & crafts building, a carpentry shop, a small sawmill, barns, garages, sheds, and an ice house totaling 29,560 sq. ft. There were also 4 houses, with approximately 20 rooms, and a small barn at the Anchor Ranch site.

As an aside, because the name "Los Alamos" was considered classified information, the installation was variously identified as Site Y, Project Y, the Zia Project, or Santa Fe Area L. However, most residents of Los Alamos and Santa Fe simply referred to it as "The Hill".

Manhattan Project Heritage Preservation Association

Manhattan Engineering District

Project Y