In 1775 Governor Jonathan Trumbull recommended the building of a fortification at the port of New London to protect the seat of the government of Connecticut. Built on a rocky point of land near the mouth of the Thames River on Long Island Sound, the fort was completed in 1777 and named for Governor Trumbull, who served from 1769 to 1784. In 1781 during the Revolutionary War, the fort was attacked and captured by British forces under the command of Benedict Arnold. In the early 19th century, the fort was redesigned and rebuilt to meet changing military needs. The present fortification was built between 1839 and 1852 as a five-sided, four-bastion coastal defense fort. During the Civil War, Fort Trumbull served as an organizational center for Union troops and headquarters for the 14th Infantry Regiment. Here, troops were recruited and trained before being sent to war. Today, the fort serves as a public park and tourist attraction.

The purpose of "The Friends of Fort Trumbull State Park, Incorporated,” (i.e., “The Friends”) is to work in cooperation with Connecticut's Department of Energy and Environmental Protection (DEEP) to support its mission of bringing to the visiting public the history of Fort Trumbull and local area. In addition to historical interpretation of the fort's role in local and national history, the areas of interest to The Friends include program development, archival management and volunteer coordination.