Fort Lesley J. McNair, on the point of land where the Potomac and Anacostia Rivers join in Washington, D.C., has been an Army post for more than 200 years, third only to West Point and Carlisle Barracks, Pennsylvania, in length of service.

The military reservation was established in 1791 on about 28 acres of what then was called Greenleaf Point. Maj. Pierre C. L’Enfant included it in his plans for ‘‘Washington, the Federal City,” as a major site for the defense of the capital. An arsenal first occupied the site in 1801; earth defenses had been there since 1791.

The fortifications did not halt the invading British in 1814. With the British coming overland toward Bladensburg, Md., Soldiers at the arsenal evacuated north with as much gunpowder as they could carry, hiding the rest in a well as the Redcoats approached from two directions. About 45 British soldiers were killed and wounded from an accidental explosion when a spark ignited an open barrel of black powder.

‘‘A tremendous explosion ensued,” a doctor at the scene reported, ‘‘whereby the officers and about 30 of the men were killed and the rest most shockingly mangled.” The remaining Soldiers destroyed the arsenal buildings, but the facilities were rebuilt after the war.

Land was purchased north of the arsenal in 1826 for the first federal penitentiary. The conspirators accused of assassinating President Abraham Lincoln were imprisoned there in 1865, and after a trial found them guilty, they were executed there by hanging.

Among them was Mary Surratt, the first woman to be executed under federal orders.

A hospital was built next to the penitentiary in 1857, and Civil War wounded were treated at what then was called the Washington Arsenal. President Lincoln was a frequent visitor to the arsenal, coming to observe ordnance tests on new weaponry. He also attended the funeral for 21 women who on June 17, 1864, were killed by the explosion of a bin of gunpowder in the room in which they were assembling cartridge cases by hand. A spark ignited some fireworks drying outside the building causing the explosion, one of the worst catastrophes to occur in the city of Washington.

The arsenal was closed in 1881, and the post transferred to the Quartermaster Corps. It was known by the name Washington Barracks. A general hospital was located at the post from 1898 until 1909. Maj. Walter Reed worked there and found the area’s marshlands an excellent site for his research on malaria. The major died of peritonitis after anappendectomy at the post in 1902.

The post dispensary and the visiting officers’ quarters now occupy thebuildings where Reed worked and died.

About 90 percent of the present buildings on the post’s 100 acres were built, reconstructed or remodeled by 1908.

With the birth of the Army War College in 1901, Fort McNair became the Army’s center for the education and training of senior officers to lead and direct large numbers of troops. Its first classes were held in 1904. The institution was reorganized as the Army-Navy Staff College in 1943 and became the National War College in 1946.

The Army Industrial College was founded at Fort McNair in 1924 toprepare officers for high-level posts in Army supply organizations and to study industrial mobilization. It evolved into the Industrial College of the Armed Forces. ICAF and NWC became the National Defense University in 1976.

FMMC acquired an additional eight acres of land at Fort McNair in 2005. Construction of a new 250,000 square foot academic and conferencing center for the National Defense University and a new physical fitness center for the post was underway in 2007. Gates have been upgraded at Fort McNair to stay abreast of security requirements. As thenew NDU building is completed,another access gate to Fort McNair will be constructed along 2nd Street. Future construction will include an operations facility for the Joint Force Headquarters-National Capital Region.

The post was renamed in 1948 to honor Lt. Gen. Lesley J. McNair,commander of Army Ground Forcesduring World War II. McNair washeadquartered at the post and was killed in Normandy, France, July 25, 1944.

Fort McNair has been theheadquarters of the U.S. Army Military District of Washington since 1971. Also assigned to the post is Company A, 3rd U.S. Infantry (The Old Guard). Thisceremonial company is known as the Commander-in-Chief’s Guard. The Soldiers wear colonial uniforms and drill under orders published during the Revolutionary War in Baron Frederick Von Steuben’s ‘‘Blue Book.”