Fort Myer is a U.S. Army post adjacent to Arlington National Cemetery in Arlington County, Virginia, across the Potomac River from Washington, D.C. It is a small post by U.S. Army standards, and has no ranges or field training areas.

As a result of the 2005 Base Realignment and Closure (BRAC) initiative to create more efficiency of efforts, the Army’s Fort Myer and the Marines’ Henderson Hall will become the first Joint Base in the Department of Defense. Joint Base Myer – Henderson Hall (JBMHH) will consist of military installations at Fort Myer, Virginia, Crystal City, Pentagon, Fort McNair, the District of Columbia, and Henderson Hall – Headquarters Marine Corps, Virginia. These installations and departments serve over 150,000 active duty, DoD civilian, and retired military personnel in the region.

Fort Myer traces its origin to the Civil War. It was originally established as Fort Whipple, after Brevet Major General Amiel Weeks Whipple died during the American Civil War in 1863. Whipple Field was named in his honor. It was renamed for Brigadier General Albert J. Myer in 1880, who established the Signal School of Instruction for Army and Navy Officers there in 1869. Since then it has been an important Signal Corps post, and a base for Army cavalry.

Fort Myer was the site of the first flight of an aircraft at a military installation. Several exhibition flights by Orville Wright took place here in 1908 and 1909. On September 18, 1908 it became the location of the first aviation fatality, as Lt. Thomas Selfridge was killed when on a demonstration flight with Orville, at an altitude of about 100 feet, a propeller split, sending the aircraft out of control. Selfridge was killed in the crash, the first person to die in powered fixed-wing aircraft. Orville was badly injured, suffering broken ribs and a leg.

The first Chief of Staff of the Army moved into Fort Myer quarters in 1908.

During World War I, Fort Myer was a staging area for a large number of engineering, artillery and chemical companies and regiments. The area of Fort Myer now occupied by Andrew Rader Health Clinic and the Commissary were made into a trench-system training grounds where French officers taught the Americans about trench warfare.

It is listed on the National Register of Historic Places.

Fort Myer is headquarters to service personnel working throughout the National Capital Region. The base provides housing, support, and services to thousands of active-duty, reserve and retired Soldiers, Sailors, Airmen, Reservists, and Marines, members of the U.S. Coast Guard and their families stationed in the United States Army Military District of Washington. The JBMHH’s mission is to operate the Army’s community and support Homeland Security in the nation’s capital.

Based here are: The First and Fourth battalions of the 3rd U.S. Infantry Regiment, (The Old Guard) — except for 'A' Company (Commander in Chief's Guard), which is stationed at Fort McNair, D.C; The U.S. Army Band “Pershing's Own”; The grave site of Black Jack, the riderless horse in the state funerals of General of the Army Douglas MacArthur and U.S. Presidents John F. Kennedy, Herbert Hoover and Lyndon B. Johnson, is located on Summerall Field, 200 feet northeast of the parade ground's flagpole.

Due to its proximity to Arlington National Cemetery, this is also the base of operations for most Services' Honor Guards and burial teams. A large percentage of burials in Arlington National Cemetery originate from Old Post Chapel, one of the two chapels on Fort Myer.

Some of the cultural attractions on post are the Caisson stables, Conmy Hall, and the Old Guard Museum.

The military's largest child development center, named the Cody Child Development Center (CDC), is located here.