The 81st Readiness Division ("Wildcat") was a formation of the United States Army originally organized as the 81st Infantry Division during World War I. After World War I, the 81st Division was allotted to the Organized Reserve as a "skeletonized" cadre division. In 1942, the division was reactivated and reorganized as the 81st Infantry Division, and served in the Pacific during World War II. After World War II, the 81st Infantry Division was allotted to the Organized Reserve (known as the United States Army Reserve after 1952) as a Class C cadre division, and stationed at Atlanta, Georgia. The 81st Infantry Division saw no active service during the Cold War, and was inactivated in 1965.

In 1967 the division's shoulder sleeve insignia was reactivated for use by the 81st Army Reserve Command (81st ARCOM). From 1967 to 1995, the 81st ARCOM was headquartered in East Point, Georgia, commanded and controlled Army Reserve units in Georgia, South Carolina, Puerto Rico and portions of North Carolina, Florida and Alabama. During that time, the 81st ARCOM was responsible for deploying US Army Reserve units to Vietnam, Southwest Asia, and the Balkans. The 81st was relocated in 1996 to Birmingham, Alabama and reorganized as the 81st Regional Support Command (RSC) and was responsible command and control of all Army Reserve units in the southeast United States and Puerto Rico.

In 2003, the 81st RSC was reorganized as the 81st Regional Readiness Command (RRC), but retained essentially the same mission as its predecessor. In September 2008, the 81st RRC inactivated at Birmingham, Alabama. In its place, a reorganized 81st Regional Support Command (RSC) was activated at Fort Jackson, South Carolina. Unlike its predecessor units, the new 81st RSC had a fundamentally different mission. Gone was the responsibility for hundreds of Troop Program Units (TPU) units and Soldiers. Instead, the 81st RSC provided Base Operations (BASOPS) support to 497 Army Reserve units in nine southeastern states plus Puerto Rico and the US Virgin Islands. By providing the essential customer care and services, the 81st RSC was intended to help the supported Operational, Functional and Training (OF&T) commands to focus on their core unit mission and ultimately meet force requirements for global combatant commanders. In 2018, the 81st RSC was provisionally redesignated as the 81st Readiness Division, and designated to gain additional responsibilities from other Army Reserve Functional Commands in addition to the enduring BASOPS mission.

On 1 October 2018, the 81st RSC was officially reorganized as the 81st Readiness Division (USAR).