 During the American Civil War, companies of the regiment loyal to the recognized Union state government in Wheeling were later combined to form the Union Army's 5th and 9th West Virginia Infantry regiments, aiding in the defeat of Confederate troops in West Virginia, Ohio and Virginia.The 150th Cavalry has also deployed in support of World War I, the Border War with Mexico, World War II, Operation Spartan Shield, the Iraq War and the intervention in Syria.The lineage of the 150th Cavalry Regiment dates back to 1 March 1778, with the formation of the Militia of Greenbrier County.