Aerial rocket artillery is a type of armed helicopter unit that was part of the artillery component of the United States Army's two airmobile divisions during the Vietnam War. Controlled by division artillery and not the aviation group, the 2nd Battalion, 20th Artillery, 1st Cavalry Division and the 4th Battalion, 77th Artillery, 101st Airborne Division, along with Battery F, 79th Artillery, 1st Cavalry Division, were the only ARA units fielded during that conflict. The ARA concept disappeared from Army aviation by the mid-1970s, replaced by more generic attack aviation units.

The 20th Field Artillery Regiment is a field artillery regiment of the United States Army constituted 1 July 1916 in the Regular Army. It served in France during the First World War with the 5th Division, at St. Mihiel and Lorraine before inactivation on 5 September 1921 at Camp Bragg, North Carolina.