Today, the descendants of these first regiments - the 181st Infantry, the 182nd Infantry, the 101st Field Artillery, and the 101st Engineer Battalion of the Massachusetts Army National Guard – share the distinction of being the oldest units in the U.S. military. December 13, 1636, thus marks the beginning of the organized militia, and the birth of the National Guard's oldest organized units is symbolic of the founding of all the state, territory, and District of Columbia militias that collectively make up today's National Guard.
What is the oldest Army National Guard Unit? The oldest Army National Guard units are the 101st Engineer Battalion, the 101st Field Artillery Regiment, the 181st Infantry Regiment, and the 182nd Infantry Regiment, all of the Massachusetts Army National Guard. These four units are the descendents of the original three militia regiments organized by colonial Massachusetts legislation on December 13, 1636, and share the distinction of being the oldest units in the U.S. military.