Fort William and Mary

Erected by local colonial forces prior to 1632, the original fortress reported directly to the royal governor of the Province of New Hampshire and guarded access to the harbor at Portsmouth. It was later manned by provincial troops and served as the colony's main munitions depot and seaport. In 1683, Governor Edward Cranfield fired longtime commander Captain Elias Stileman and replaced him with Walter Barefoote. Colonel Shadrach Walton commanded the fort during different periods at the end of the 17th and beginning of the 18th century. The fort also served to protect Kittery on the opposite shore of the harbor, now in the state of Maine, but then part of the Province of Massachusetts Bay. The Kittery side of the harbor was raided numerous times by the tribes of the Wabanaki Confederacy during the French and Indian Wars (1753–1763). == American Revolution ==

In 1774, it was the only permanently occupied military post in New Hampshire. 1774 raids (1705) On December 14, 1774, local Patriots from the Portsmouth area, led by local political leader and rebel activist John Langdon, stormed the post (overcoming a six-man caretaker detachment) and seized the garrison's gunpowder supply, which was distributed to local militia through several New Hampshire towns for potential use in the looming struggle against Great Britain. On the following day, rebels led by colonial military officer John Sullivan again raided the fort, this time seizing with greater effort numerous heavy cannon, ammunition and supplies. == Fort Constitution ==

Following the Revolution, the fort was called "Castle Fort" or "Fort Castle". On July 4, 1809, an accidental explosion marred Independence Day / Fourth of July celebrations at the fort, killing a number of soldiers and civilians. The U.S. Secretary of War's December 1811 report on fortifications described Fort Constitution as "an enclosed irregular work of masonry, mounting 36 heavy guns... (with) brick barracks for two companies..." During the War of 1812 the fort was occupied and expanded with Walbach Tower, a Martello tower with a single 32-pounder cannon, being built in 1814, just before the conflict ended. Over four decades later, during the American Civil War (1861–1865), Fort Constitution was projected to be rebuilt as a three-tiered granite fort under the new expanded, more formidable Third System of U.S. coastal defense fortifications. However, advances in weaponry, particularly the development and use of armored, steam-powered warships with heavy rifled guns, rendered the masonry walls design obsolete before they were finished. The fort's construction was abandoned in 1867 following the Civil War with the older now-obsolete Second System fort still largely intact and two walls from the revised expanded Third System cut short, built around parts of it. Named for Union Army Brigadier General Elon J. Farnsworth (1837–1863), killed at the Battle of Gettysburg during the Civil War, the battery was completed in 1899, a year after the successful conclusion of the Spanish-American War. It was joined in 1904 by the construction of adjacent Battery Hackleman, built primarily to defend a newly created underwater minefield against enemy minesweepers. Named for Union General Pleasant A. Hackleman, it had two 3-inch (76 mm) M1903 guns on pedestal mounts. The pair of fortifications were similar to numerous other Endicott-style defenses built during the late 1890s and early 1900s on river mouths, harbors, and bays outside of major cities along the Eastern Seaboard and Gulf of Mexico. After the American entry into World War I in April 1917, many guns were removed from coast defenses for shipment across the Atlantic Ocean to potential service on the Western Front. Both 8-inch guns of Battery Farnsworth were removed in October 1917 for use as railway artillery. In 1920 a mine casemate was built next to Battery Farnsworth to replace a similar facility at nearby Fort Stark. During World War II (1939/1941-1945), Battery Hackleman's 3-inch guns were sent to a new battery of the same name further south at Fort H. G. Wright on Fisher's Island, New York. They were replaced by two 3-inch (76 mm) M1902 guns taken from Battery Hays (named for Union Army General Alexander Hays, killed at the Civil War Battle of the Wilderness) at Fort Stark. In 1940–1944 the Harbor Defenses of Portsmouth were garrisoned by the 22nd Coast Artillery Regiment of the U.S. Army, and a mine observation station was built atop Battery Farnsworth. Following the surrender of the Axis powers, Battery Hackleman was disarmed by 1948 and the fort was turned over to the Coast Guard. Battery Hackleman was eventually demolished, but Battery Farnsworth can still be seen as part of the subsequent state park. The Fort Constitution site was given back to the State of New Hampshire by the American military in 1961 and turned into a state park. It was listed on the National Register of Historic Places in 1973. As of 2025 the park is temporarily closed. == The lighthouse ==

, 2016 The fort has been home to a lighthouse since 1771. The current installation, the Portsmouth Harbor Light, was completed in 1878. Its Fourth Order Fresnel lens remains a valuable aid to navigation. The tower and the grounds immediately around it are open for scheduled tours. ==See also==