In early 1942, the 23rd Armored Engineer battalion constructed Camp Iron Mountain with over 40 miles of gravel roads, firing ranges, walkways, and thousands of 6-man pyramidal tents. In addition, the camp had 15 shower buildings, 26 latrine buildings, an amphitheatre, four elevated water tanks and over 9,300 feet of water pipes with two centrifugal pumps and a chlorinator to supply the camp with fresh water from the Metropolitan Aqueduct. The camp was laid out in a design typical of all DTC camps- a rectangular shape roughly 2-3 miles wide and a mile deep, and rocks were used to line roads, walkways, tent areas, native plants, mess areas, etc...  Camp Iron Mountain is unique in that is has two altars built of a stone- an Episcopalian and Catholic one, each on either side of the camp. Additionally, there are the remnants of a contour relief map in a 200 x 175 foot area that was built by the Army Corps of Engineers. The map covered the area from Phoenix to Indio, and from Needles to Yuma, and was complete with small wooden signs indicating topographoc features, railroads, roads, mountains, cities and other DTC camps. The wood footbridge walkway over the map is no longer there and the small wood signs to identify the mountain ranges are faded.

The first unit to occupy the camp was the 3rd Armored Division in the early summer of 1942. Other known units who were stationed there include: 183rd Artillery, 951st Artillery Battalion, 7th Motorized Division, 5th Armored Division, 191st Field Artillery Brigade, and the 54th Evacuation Hospital.

Iron Mountain is likely the best-preserved camp, as prior to the establishment of California Highway 62 the area was extremely isolated.  However, this isolation protected the camp from vandalism.  Today, rock-lined walkways and roads as well as unit insignia are still clearly visible at Camp Iron Mountain.