It was founded by a number of the District's earliest residents, including Benjamin Ogle Tayloe, Peter Force, and J. Carroll Brent, together with 28 other prominent Washingtonians, on December 7, 1865 — a time of great changes to the city and its population following the American Civil War.
Over the years the AOI has supported many important civic initiatives including construction of the District Building, the installation of modern city street lighting, and the adoption of Washington's flag in 1938.
The AOI commissioned a biographical commemorative plaque that was placed at the base of the statue (located on the NE corner of the John A. Wilson (District) Building) in November 2010.
On July 4, 1920, the AOI invited members of a parallel African-American organization, The Association of the Oldest Inhabitants (Colored), Inc., to a joint meeting to recognize the District of Columbia's fallen veterans of the Great War (1917-1918).
After a campaign, assisted by the "Washington Post's" John Kelly, 20 years of the AOI Colored's more recent records were serendipitously located by DC author/historian James Goode while conducting research for a book.