It is located 37 miles (60 km) northeast of Barstow, in the Calico Mountains.
The National Training Center is part of the US Army Forces Command (FORSCOM).
A fur trapper, Smith was soon followed by other pioneers traveling the Old Spanish Trail between Santa Fe and Los Angeles.
The trail crossed the area on the eastern edge of Fort Irwin, between Salt Spring and the Mojave River.
The Old Spanish Trail passed through Silurian Valley, then west through the Avawatz Mountains at Red Pass and beyond the playa of Red Pass Lake, through a gap between the Soda and Tiefort Mountains to Bitter Spring in a wash in the next valley.
Bitter Spring was the only reliable watering and grazing place along the route.
The Fort Irwin area has a history dating back almost 15,000 years, when Native Americans of the Lake Mojave Period were believed to live in the area.
Soon railroads, workers, and businesses led to the establishment of the nearby town of Barstow.
During the re-opening of the National Training Center in 1980, the OPFOR consisted of Re-activation of the 6/31st regiment Polar Bears,of infantry from the 7th Infantry Division US Army based in Fort Ord, California, and the 1st Bn, 73rd Armor. Air support and air combat tactics came from USAF tactical fighter wings operating from nearby Nellis AFB and George AFB, USN attack and strike fighter jet squadrons from NAS Lemoore, USMC attack and fighter/attack jet squadrons operating from MCAS El Toro, and USMC helicopter light attack squadrons operating from MCAS Tustin.
Once the US Army turned to regimental units in 1985, the OPFOR was designated the 177th Armored Brigade (SEP). When George AFB, MCAS El Toro and MCAS Tustin were closed as a result of Base Realignment and Closure Commission actions in the mid-1990s, USAF air support shifted to a combination of composite wings and fighter wings from Nellis AFB, Hill AFB, Luke AFB and Davis-Monthan AFB, and USMC air support shifted to MCAS Miramar (formerly NAS Miramar), MCAS Yuma and MCAS Camp Pendleton.
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.
The California Gold Rush brought prosperous trade and unexpected trouble to the area.