Fort Mott was part of a three-fort defense system designed for the Delaware River during the postbellum modernization period following the American Civil War. The other two forts in the system were Fort Delaware on Pea Patch Island and Fort DuPont in Delaware City, Delaware. They are connected by the Three Forts Ferry Crossing.
Original plans for Fort Mott specified eleven gun emplacements with twenty guns and a mortar battery with six emplacements for Rodman Smoothbore guns. Construction was started in 1872, however, only two of the gun emplacements and two magazines in the mortar battery were completed by 1876 when all work stopped.
A general War Department Order #72, issued on December 16, 1897, designated the new fort as Fort Mott, in honor of Major General Gershom Mott, of Trenton. Gershom Mott had served with distinction as Second Lieutenant in the Tenth Infantry in the Mexican-American War, as Lieutenant-Colonel in the 5th New Jersey Volunteer Infantry, as Colonel and commander of the 6th New Jersey Volunteer Infantry before he was promoted to first Brigadier General. He was wounded four times, resigned from the Army in 1866 and died on November 29, 1884.
Fort Mott, along with Fort Delaware and Fort DuPont, became obsolete as the principal defensive installation on the Delaware River with the construction of Fort Saulsbury, near Milford, Delaware, shortly after World War I.
Troops were regularly stationed at Fort Mott from 1897 to 1922. The federal government maintained a caretaking detachment at the fort from 1922 to 1943. New Jersey acquired the military reservation as a historic site and State park in 1947. Fort Mott State Park was opened to the public on June 24, 1951. The site is operated and maintained by the New Jersey Division of Parks and Forestry. It is located in Pennsville Township, New Jersey.
Apart from regular practice sessions and testing, the guns at Fort Mott were never fired in battle.
As part of a budget reduction, the park is slated to close pending the adoption of the new state budget.
Fort Mott is part of the Fort Mott and Finns Point National Cemetery District, listed on the National Register of Historic Places.