Fort Stark is a former military fortification in New Castle, New Hampshire, United States.

Located at Jerry's Point (also called Jaffrey's Point) on the southeastern tip of New Castle Island, most of the surviving fort was developed in the early 20th century, following the Spanish–American War, although there were several earlier fortifications on the site, portions of which survive.

The fort was named for John Stark, a New Hampshire officer who distinguished himself at the Battle of Bennington in the American Revolution.

In 1887 the Jerry's Point Lifesaving Station was built on the west side of the site, which remained in service until 1908 when the Portsmouth Harbor Lifesaving Station was built on Wood Island near Fort Foster.

[3] In 1885, the Endicott Board recommended a large-scale fortification plan that eventually included Fort Stark.

In 1898, shortly after the outbreak of the Spanish–American War, emergency batteries were constructed to quickly arm key points, as most of the Endicott batteries were still years from completion and it was feared the Spanish fleet would bombard the US East Coast.

[5] After the American entry into World War I the two 6-inch (152 mm) guns of Battery Kirk were dismounted for use on the Western Front on field carriages.

[1] A history of the Coast Artillery in World War I states that none of the regiments in France equipped with 6-inch guns completed training in time to see action before the Armistice.

The Navy used the fort for harbor defense purposes until 1953, when it became a reserve training center for a Mobile Inshore Undersea Warfare Unit until 1980.

The fort is now a state park, with a small museum in the Visitors' Center that includes the remaining 3-inch gun.