Fort Knox State Historic Site – Prospect, Maine - Atlas Obscura

Fort Knox State Historic Site

Prospect, Maine

This 19th century granite fortification is one of the most well preserved forts in New England. 


This stunning granite fortification in Maine, built between 1844 and 1869, was named after Henry Knox, a general in the Revolutionary War. However, decades before the fort was constructed, Maine unfortunately did not fare too well during the American Revolution.

Maine, which was actually still part of Massachusetts at the time, suffered embarrassing defeats by the British Navy during the Revolutionary War and again in the War of 1812. (Incidentally, these defeats led to the push to make Maine its own state, as it was too difficult to defend as part of Massachusetts.)

When the Aroostook War began in 1838, it revived fears about the region’s vulnerability, which led to the construction of Fort Knox, an ambitious coastal fortification built between 1844 and 1869 (though never fully completed) of granite rather than wood like previous forts. Located on the bank of the Penobscot River in Prospect, Maine, it is a beautiful example of military architecture, and was sure to defend against a third defeat. 

With two batteries facing the river with canons ready to fire at approaching ships, the fort was ready for action. However although it was manned during the Civil War and Spanish–American War, it never saw a battle. The impressive fortification was eventually purchased by the state of Maine in 1923 and preserved as a state historic site. Today Fort Knox (also known as Fort Knox State Park or Fort Knox State Historic Site) is one of the most well preserved forts on the New England coast. In 1970 it was also designated National Historic Landmark.

Know Before You Go

If you're visiting the fort also check out the Penobscot Narrows Bridge and Observatory, the first bridge observation tower in the U.S. which offers beautiful views of Fort Knox and the surrounding area.