Once an active Coast Artillery post, it was manned by hundreds of soldiers and bristled with mortars and guns that controlled the southern approaches to Boston and Quincy Bay.

[4] With a range of 7 miles, these batteries could reach both the northern and southern channels into the harbor, interlocking with the fire of Fort Banks' mortars.

When fully equipped, these pits contained 16 12-inch coast defense mortars, able to bombard the southern approaches to the harbor with projectiles weighing over 1,000 pounds (450 kg) each.

[5] The Boston press reported that when the mortars were test-fired in the 1920, they literally blew doors off of nearby barracks buildings and broke windows at the fort.

[2] By the 1920s, Fort Andrews consisted of some 30 structures (see map at left), ranging from large brick barracks buildings that housed over 100 soldiers each to elegant officers' quarters and a 50-bed hospital.

In 1942 the fort's massive coast defense mortars were scrapped, but its 6-inch and 3-inch guns served out the war guarding the southern approaches to Boston Harbor.

[9] In 2010, most of the fort's structures were seriously dilapidated or in danger of collapse, and Peddocks Island, normally reachable by ferry from Hull, was temporarily closed to the public.

[10] This structure originally contained a vertical base end station for Battery McCook, as well as observation instruments for the Commander of the fort and a plotting room.

The third fire control station on the east side, also built in 1925, was the small pillbox that housed a second depression position finder (DPF) for Battery McCook.

Today, the structure is thickly overgrown with trees and brush, but during World War II controlled burns kept the brow of the hill clear of obstructions.

The final fire control structure is a two-bay wood and plaster building that was 40 ft. long overall, constructed in 1907, and had dual observation platforms and plotting rooms for mortar batteries Whitman and Cushing, northwest of the parade ground.

The ruins are significant for being the only remains of one of the early wood and plaster fire control buildings that were so prevalent throughout Boston's harbor defenses in the period 1905-1925.