The 149th Armored Regiment was an armored regiment that was part of the California Army National Guard. Its lineage dates back to a cavalry unit organized in 1895 in Salinas. As Troop C, the unit's first major action occurred when it deployed to help in the aftermath of the 1906 San Francisco Earthquake. In 1916, still as Troop C, the unit served along the Mexico–United States border near Nogales, Arizona to deter further border incursions, due to events surrounding the Pancho Villa Expedition. The following year, Troop C was activated then reorganized and redesignated as Company B, 145th Machine Gun Battalion upon the United States' entry into World War I; as part of the 40th Division, the battalion deployed to France in 1918, and returned to the United States in 1919.

The California Army National Guard is one of three components of the California National Guard, a reserve of the United States Army, and part of the National Guard of the United States. The California Army National Guard is composed of 18,450 soldiers. Nationwide, the Army National Guard comprises approximately one half of the US Army's available combat forces and approximately one third of its support organization. National coordination of various state National Guard units are maintained through the National Guard Bureau.