4 Must-See Historic Forts In Connecticut

Four working historic forts sit within easy driving distance across Connecticut, each tied to a different American war. Fort Griswold in Groton stands above the Thames River where the bloodiest Revolutionary War engagement on Connecticut soil took place in 1781. Fort Nathan Hale in New Haven and Fort Trumbull in New London both defended harbors that British forces had already targeted. Fort Saybrook in Old Saybrook is the oldest of the four, with foundations laid in 1635 at the mouth of the Connecticut River. Together they cover the state's military history through the Pequot War and the Cold War.

Fort Griswold Battlefield State Park, Groton

The Battle of Groton Heights at Fort Griswold on September 6, 1781, was the bloodiest engagement of the American Revolutionary War on Connecticut soil. British troops landed on both sides of the Thames River and overran the fort after its defenders ran low on ammunition. Today the Groton Monument, a 135-foot granite obelisk completed in 1830, stands over the battle site as a memorial to the fallen.

The Monument House Museum, built in 1830, holds artifacts from the battle along with a painting, a model of the fort, and a stained-glass window from the period. The Ebenezer Avery House, where wounded Americans were taken after the battle, opens weekends Memorial Day through Labor Day, noon to 4 p.m.

Fort Nathan Hale, New Haven

Built in 1776 as Black Rock Fort, the site was established to protect the Port of New Haven. On July 5, 1779, British forces under General William Tryon raided New Haven as part of Tryon's broader Connecticut coastal campaign, capturing the fort's nineteen defenders after they ran out of ammunition and burning the barracks as they withdrew. Around 1806 the federal government purchased the site to build a masonry fort mounting nine guns and a barracks. The War of 1812 brought the U.S. Corps of Artillery to garrison the site, and the fort was renamed for the American patriot Nathan Hale around that time.

The second Fort Hale, built between 1863 and 1866 to mount eighteen guns and house five bunkers, saw no Civil War action. The site transferred to the State of Connecticut in 1921 and now operates as a public park.

Fort Trumbull State Park, New London

Fort Trumbull's history spans two and a half centuries of American military service, covering the Revolution, the Civil War, World War II, and the Cold War. The first fort went up in 1777 to protect New London Harbor against British attacks; the site later became part of the national coastal defense system. The third and current Fort Trumbull, built between 1839 and 1852, stands on sixteen acres of riverfront granite with views over the Thames River.

The fishing pier offers more than 500 feet of shore access. Seasonal water taxi tours led by knowledgeable guides run during the summer (June through September in 2026), connecting the fort to the New London waterfront across the river.

Fort Saybrook Monument Park, Old Saybrook

Fort Saybrook was the first military post built on the Connecticut River and the site where the heaviest fighting of the Pequot War took place. The first fort, built between 1635 and 1636, burned down in the winter of 1647 to 1648. A new structure went up north of the original and was later renamed "Fort Fenwick" during the War of 1812. Today the seventeen-acre park sits at the mouth of the river with panoramic water views and educational signs throughout the grounds. The park is open daily during daylight hours.

Discover Historic Connecticut

Connecticut's four working forts cover three centuries of American military history. Fort Saybrook traces back to the 1630s. Fort Griswold marks the Revolution's bloodiest day on Connecticut soil. Fort Nathan Hale and Fort Trumbull defended New Haven and New London through the War of 1812 and stayed in service through World War II. All four sit within easy driving distance, and all stay open to visitors year-round.