4 Must-See Historic Forts In New Hampshire

New Hampshire holds the distinction of being the first of America’s original Thirteen Colonies to declare independence from Great Britain. As a result, it is also where some of the earliest acts of armed rebellion against British rule occurred. Founded in 1623 when English settlers landed at Odiorne Point in what is now Rye, the Granite State's strategic Atlantic coast location and its position on the northern frontier made it essential to colonial defenses for more than three centuries. In fact, the state's motto, "Live Free or Die," reflects the fierce independence of its early settlers and the military installations they built. From frontier wooden palisades to massive concrete gun emplacements built 300 years later, these still-impressive fortifications tell the fascinating tale of a state that served as both a buffer against French and Native American forces and the guardians of New England's most important harbors.

Fort Constitution, New Castle

Originally known as "The Castle" and later Fort William and Mary, Fort Constitution is one of the most historically significant military sites in the United States. It was here on December 14, 1774, that the first organized armed resistance of the American Revolution took place when local Patriots stormed the fort and seized the garrison's gunpowder supply.

Situated on a strategic peninsula at the northeast corner of New Castle Island, the fort was built to guard the entrance to Portsmouth Harbor in 1631, making it one of the oldest military installations in the country. Its claim to fame, however, came on December 13, 1774, when Paul Revere rode from Boston to Portsmouth to warn that British troops were coming to reinforce the fort and secure its munitions. The next day, several hundred men from Portsmouth, New Castle, Rye, and Kittery attacked the fort, overwhelming the British garrison and nabbing 100 barrels of gunpowder.

A second raid on December 15 saw several cannons seized, some of them used later at the Battle of Bunker Hill. Considered acts of treason, the attacks were punishable by death and marked a point of no return in the colonies' relationship with Britain.

Pay a visit to Fort Constitution State Historic Site today, and you’ll see a structure that now includes Battery Farnsworth, completed in 1899 with two 8-inch guns. You can also explore the remains of Walbach Tower, built during the War of 1812, with views of the Portsmouth Harbor Light, completed in 1878, with its original lens still in use. Self-guided tours are available and feature fascinating interpretive panels explaining the fort’s evolution.

Fort Stark, New Castle

Just a short distance from Fort Constitution and on the southeast corner of New Castle Island, Fort Stark has commanding views over the Piscataqua River, Little Harbor, and the Atlantic Ocean. Named after the commander of New Hampshire forces at the Battle of Bennington in 1777, Fort Stark is one of seven forts built to protect Portsmouth Harbor and the Portsmouth Naval Shipyard. The site's military history spans from the late 18th century through World War II, with the current concrete fortifications dating primarily from the 1940s.

Used primarily for reserve training until it was deeded to the state of New Hampshire, the fort's World War II-era structures include concrete gun emplacements, underground magazines, and observation posts. Battery Hunter and other defensive positions were constructed to protect against potential German U-boat attacks and surface raiders that might threaten the vital Portsmouth Naval Shipyard.

Pay a visit to Fort Stark State Historic Site and you’ll enjoy 10 acres of historic fortifications via a self-guided walking tour. A visitor center features military and shipwreck exhibits and is open by appointment, as are guided tours.

Fort At Number 4, Charlestown

A mid-18th-century stockade fortification, Fort at Number 4 (aka, Fort at No. 4) was used to protect the northernmost British settlement along the Connecticut River during the French and Indian War. Located in present-day Charlestown, NH, the original fortification was constructed in 1744 when townspeople voted to connect six homes together to form a fortified rectangle. Joined together by lean-tos with a two-story structure featuring a Great Hall and a guard tower at the southern end, this ad hoc structure was to play a crucial role in protecting English settlers during a tumultuous time in the colony’s history.

It was put to the test in 1747 when just 31 men successfully defended the community against a large enemy force during a three-day siege. After this inspiring success, the fort was never attacked again, though it later served as a staging area for a militia of 1,500 men from New Hampshire and Massachusetts before their march to Bennington.

Reconstructed in 1960 to look as it would have during King George's War of 1744-1748, the Fort at No. 4 Open-Air Museum is a first-rate living history museum that hosts both French and Indian War and Revolutionary War reenactments. Costumed interpreters demonstrate period crafts including blacksmithing, cooking, and musket drills, all adding up to a fun and immersive look at 18th-century military life. The museum's collection includes authentic period furnishings, tools, and weapons, with the Great Hall serving as the centerpiece.

Fort Dearborn At Odiorne Point State Park, Rye

One of New Hampshire’s “newer” old fortifications, Fort Dearborn was constructed between 1942 and 1947 to protect Portsmouth Naval Shipyard and Portsmouth Harbor as part of an extensive modernization of U.S. coastal defences. Now preserved within Odiorne Point State Park, its original concrete structures remain impressive.

The largest, Battery Seaman, featured two 16-inch guns in heavily reinforced concrete casemates and was capable of firing huge 2,000-pound shells a distance of up to 25 miles. Battery 204, consisting of two shielded 6-inch guns, featured a large bunker containing magazines and fire control facilities. After the war, the fort was deactivated and all guns removed before the area became a state park in the 1960s.

Today, you can explore the remains of Fort Dearborn at Odiorne Point, with parts of Battery Seaman still accessible. Battery 204, near the Seacoast Science Center, displays several 16-inch shells and interpretive panels about the fort's history.

The Final Word

New Hampshire's surviving historic forts are well worth a visit. Together, these fascinating structures are a rare chance to experience nearly 400 years of American military history, all within a relatively small geographic area. From Fort Constitution's colonial-era foundations and Revolutionary War significance to Fort Dearborn's massive World War II concrete gun placements, these four remarkable military attractions provide a fascinating look at the evolution of America’s coastal and frontier defences.