The Montana Army National Guard was originally formed in 1867.
The 163d Infantry dates its history to independent companies grouped together around 1900.
The Militia Act of 1903 organized the various state militias into the present National Guard system.
The 163rd Infantry Regiment of the Montana Guard formed part of the 41st Infantry Division, which fought through the Pacific during World War II.
The Regiment was inducted into the Regular Army in September 1940, and were sent to Camp Murray at Fort Lewis, Washington.
They participated in large-scale military exercises in California in 1941.
On 7 Dec. 1941 small units were detailed to guard the Washington coastline from Japanese saboteurs.
In March 1942 they were sent to Australia. Their engagements included the Battle of Buna-Gona, the Salamaua-Lae campaign,
Operations Reckless and Persecution and the Battle of Biak, as well as the liberation of the Philippines.
In September 1945 the Regiment went ashore at Hiro, Japan as part of the occupation of that country.
By this time most of the original Montanan troops had been discharged.
The Montana ARNG maintained the 163rd Armored Cavalry Regiment (whose roots date back to 1884), at least until 1988.
In 1985 its units included the 1/163 Cavalry, the 2/163 Cavalry, the 3/163 Cavalry (based in Texas), an Air Troop, an Attack Helicopter Troop (based in Utah),
and the 1063rd Engineer Company. The MT ARNG maintained the 163rd Armored Brigade until 1995.
When the 163rd Armored Brigade disbanded, the 1-163 Battalion was reassigned to the 116th Cavalry Brigade headquartered in Idaho.
Commonly referred to as "the Griz Battalion", the 1-163rd at first was designated as a Cavalry Regiment in 1953, named the 163rd Cavalry Regiment.
The unit was renamed the 1-163rd Infantry Battalion during the 2006 reorganization of the Montana Army National Guard,
and has been re-designated as Cavalry once again, combining mechanized infantry with Abrams tank units.
In April 2010, the 163rd Cavalry Regiment (formerly the 1-163 Infantry)
received mobilization orders and prepared to deploy to the Middle East for the second time in five years.