Established in 1941, Fort A.P. Hill is the Joint Force's premier all-purpose, year-round, training destination. Encompassing nearly 76,000 acres of diverse terrain, including a 27,000 acre live fire complex.
 
Beginning early 1942, preparations were underway to train and organize the Task Force which was to occupy North Africa. Gen. George S. Patton had over 26,000 of his troops of the 2nd Armored Division, the 3rd and 9th Infantry Divisions train at Fort A.P. Hill.
 
Over the course of the war hundreds of thousands of troops trained at the Reservation. The training units were so diverse as to include; armored divisions, anti-tank units, anti-aircraft, medium and heavy artillery, topographical Engineering companies and Quartermasters, infantry, hospital units, truck regiments, cavalry, coast artillery, signal battalions, ordinance and more.
 
In the autumn of 1942, Fort A.P. Hill was the staging area for the headquarters and corps troops of Major General Patton’s Task Force A, which invaded French Morocco in North Africa. 
Today, Fort A.P. Hill is still uniquely postured to meet training and range qualification requirements for a wide range of training operations for a variety of military, government and civilian customers.

It is used year-round for military training of both active and reserve troops of the ⚠Army, ⚠Navy, ⚠Marines, and ⚠Air Force, as well as other government agencies. These include the ⚠Departments of State and Interior; ⚠U.S. Customs Service; and federal, state and local security and law enforcement agencies.

The Garrison has the distinct honor of having 3d U.S. Infantry conduct much of their tactical and field training here. The 3d U.S. Infantry, traditionally known as ⚠"The Old Guard," and is the oldest active-duty infantry unit in the Army, serving our nation since 1784. The Old Guard also provides Fort A.P. Hill with ceremonial and service support.

Fort A.P. Hill is also home to the ⚠Night Vision and Electronic Sensors countermine/counter-IED capabilities test facilities, Naval Special Warfare Combat Training Center, Command Sgt. Maj. Steven W. Faulkenburg Training Complex, U.S. Army Reserve Center, home of the 310th Engineer Multi-role Bridge Company and ECS-88.

The Capt. Jason T. McMahon Explosive Ordnance Disposal Training Center was named to honor ⚠Capt. Jason T. McMahon, an EOD Soldier who was killed in action in Afghanistan on Sept. 5, 2010. McMahon was the company commander of the 744th Explosive Ordnance Disposal Company [⚠1], 184th Explosive Ordnance Disposal Battalion [⚠1] [⚠2] at the time of his death. Instructors train students on EOD Team Leader duties/responsibilities during Explosive Ordnance Disposal incident response to Conventional, Chemical / Biological incidents to include Improvised Explosive Devices (IEDs) as well as teach students to conduct team administrative/logistic integration in a direct support role with other units. 

In 2021, the Army Reserve’s 99th Regional Support Command (RSC) Maintenance Sustainment and Readiness Program relocated an Equipment Concentration Site (ECS) on the garrison to provide a platform for the maintenance and storage of military equipment and vehicles. These vehicles and equipment are for the use of all regional U.S. Army Reserve (USAR) units for mission support and training. The maintenance and storage of vehicles and equipment at the ECS allows for the reduction of vehicles and equipment at home station, requiring less real estate and reducing the maintenance workload on the units. ECS-88 is staffed with transportation and mechanic specialists. The site provides two level maintenance support as well as sustainment maintenance for USAR units in the area.

The U.S. Army Asymmetric Warfare Group officially opened Asymmetric Warfare Group Battle Lab on Jan. 24, 2014. The complex features state-of-the art training and range facilities that support the AWG mission of rapid material and non-material solution development as well as adaptability and resiliency training. The 300-acre training complex includes a headquarters, barracks, administrative, training and maintenance facilities, an urban area, a mobility range, an 800 meter known distance range, a light demolitions range and an indoor small arms range. In 2022, the Battle Lab was absorbed by the garrison and is now used for a wide variety of training by a wide variety of units.

Fort A.P. Hill Assault Landing Zone is named after a distinguished paratrooper who served with valor during World War II. George B. "Ben" Adkins was a native of Franklin County, Virginia. He left the ⚠Virginia National Guard at the start of World War II and joined the 82nd Airborne. Serving as a medic in the 505th Parachute Infantry Regiment, he was awarded two Silver Stars, one Bronze Star, a Citation for Gallantry in Action, and a Purple Heart. The Adkins Assault Landing Zone is currently used by many different types of aircraft to include the C-130 and C-17.

JROTC Annual Camp Success, a Fort A.P. Hill tradition, has occurred for over a decade. Camp Success is where Junior ROTC cadets from high schools in Delaware, Maryland, North Carolina, Virginia and Washington D.C. attend a six-day camp that broadens their horizons and instilled them with confidence.

During the War on Terror, Fort A.P. Hill's warrior training throughput was approximately 80,000 troops per year. Many of the warriors performed pre-deployment training here prior to being deployed overseas.

In 2022, Congress directed a redesignation commission to redesignate several garrisons and Fort A.P. Hill was one. On August 25, 2023, Fort A.P. Hill was redesignated Fort Mary Walker. 

In 2025 the installation was renamed Fort Anderson-Pinn-Hill (Fort A.P. Hill) for three Union Soldiers who all earned the Medal of Honor in the Civil War.

To date, training facilities include, but are not limited to, HMMWV Egress Assistance Trainer, Engagement Skills Trainer II. Training areas include Land Navigation Course's, Leadership Reaction Course, NBC Confidence Course, Obstacle Confidence Course, Rappel Tower, Rope Bridge Construction Site, Urban Operations Site, Warrior task Complex, Training areas, and Weapon Ranges.

The Garrison continues to change to meet the ever-changing needs of the warfighter. Fort Walker is just as capable of training a multitude of warriors just as it did when it was an Army reservation in 1942.