During the Second Seminole War, nearly a quarter of the U.S. Army strength was sent to Florida and Congress realized that the Army needed to be expanded and that was when it was raised to 12,539. Along with the increase in strength, housing became a big issue which was why the Army built the Plattsburgh Barracks.
A permanent Army post was planned and was to have four stone barracks surrounded by a wooden palisade.
A site was selected outside of the town of Plattsburgh and just south of the three remaining earthwork fortifications from the 1814 siege: Fort Brown, Fort Moreau and Fort Scott.
These forts had been constructed under the direction of Major Joseph Totten, an expert military engineer during the war. There were also two smaller redoubts erected later, Fort Tompkins and Fort Gaines. All five of these fortifications formed the endpoints of a pentagon which featured a field of interlocking cannon fire.