During his travels, he noted several small bands of Indians, and is believed to have been the first European to make contact with the Native Americans of the area.

The trail crossed the area on the eastern edge of Fort Irwin, between Salt Spring and the Mojave River.

From Bitter Spring the trail led 18.75 miles (30.18 km) southwest climbing Alvord Mountain to cross Impassable Pass to descend Spanish Canyon and cross the plains to the location of Fork of the Road on the north side of the Mojave River where it met the Mohave Trail.

In 1844, Captain John C. Fremont, accompanied by Kit Carson, was the first member of the US Army to visit the Fort Irwin area.

Captain Fremont established a camp near Bitter Springs as he pioneered a route that served travelers on the Old Spanish Trail, and later the Mormon Road, linking Salt Lake City to California.

This camp was later to become an important water and grazing place for pioneers crossing the Mojave Desert during California's settlement and gold rush.

In 1847, the Army's Mormon Battalion patrolled the Fort Irwin area to control the raiding and horse stealing.

In 1940, President Franklin D. Roosevelt established the Mojave Anti-Aircraft Range, a military reservation of approximately 1,000 square miles (3,000 km2) in the area of the present Fort Irwin.

Regimental tank companies of the U.S. 43d Infantry Division from Camp Pickett, Virginia were the first to train at the new facility.

In January 1971, the garrison was deactivated again and placed in maintenance status under the control of Fort MacArthur (Los Angeles), California.

On 9 August 1979, the Department of the Army announced that Fort Irwin had been selected as National Training Center (NTC).

The location – an isolated area – was ideal because of its over 1,000 square miles (2,600 km2) capacity for maneuver and ranges, its uncluttered electromagnetic spectrum, and its restricted airspace.

Among the first units to train against the Opposing Force (OPFOR) were 1st Battalion, 22nd Infantry and 1st Battalion 77th Armor, 4th Infantry Division (Mech) from Fort Carson, Colorado in Spring 1978 as a proof of concept FX for establishing Irwin as the NTC, the 3rd Battalion 67th Armor, 2nd Armored Division from Fort Hood, Texas in operation TASK FORCE IRWIN III, 1 Aug – 14 Sept, 1979, and 3rd Brigade, 1st Cavalry Division from Fort Hood, Texas in spring 1981.

Also Ft Irwin and the 1st CAV tested and implemented the Multiple Integrated Laser Engagement System (MILES).

The first MOUT (Military Operations in Urban Terrain) mission was conducted at the NTC Pioneer Training Facility in December 1993.

After the September 11, 2001 attacks, the NTC transformed to focus on continuous counterinsurgency ops that reflected a rapidly changing battlefield, especially in desert climate environments.

A common tradition for any visiting military unit is to paint their sign on one of the rock formations near the main gate.

One of the NTC features is the presence of 12 mock-up "villages" used to train troops in Military Operations in Urban Terrain (MOUT) prior to their deployment.

These are Arabic speaking roleplaying actors portraying government officials, local militia, police, military, villagers, street vendors and insurgents.

Some villages are completely instrumented, including video recording, to assist the OC/T teams in providing feedback to the training unit.

[5] The United States Census Bureau has designated Fort Irwin as a separate census-designated place (CDP) for statistical purposes, covering the residential population.

According to the 2010 United States census, Fort Irwin had a median household income of $50,469, with 12.6% of the population living below the federal poverty line.

This plan is expected to result in more than 500 MW of renewable energy with one billion kilowatt-hours (kWh) of solar power generated per year by 2022.