[3] After the American Revolution, the federal government took over the property during an expansion of the nation's coast defenses from 1794 to 1807, which is known as the First System of U.S. fortifications.

[2] The secretary of war's report on fortifications dated December 1811 describes the fort as "an enclosed work of masonry and sods, mounting eight heavy cannon, covered by a blockhouse...".

Despite lacking the ammunition and powder needed to sink or drive off the two frigates, the fort's garrison was able to bluff the British by running out all of their guns and acting as though they were preparing to attack.

[3] In 1814 the fort was named for Samuel Sewall (1757–1814), who served as Chief Justice of the Massachusetts Supreme Court from 1800 until his death in 1814.

[3] He was the great-grandson of the Salem witch trials judge of the same name, also a chief justice of the colony's highest court.

[9] The fort was nearly doubled in size by 1864 under Army engineer Major Charles E. Blunt, with a bombproof shelter added.

It was used as the mobilization site for Battery H, 1st Massachusetts Heavy Artillery, commanded by Captain Walter L. Pratt, from June to August, 1898.