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Location On Route 174, just off U.S. Route 1 in Prospect. Lat 44.566785 / Lon -68.804737

Hours / Season Open 9:00 a.m. to sunset daily from May 1st to October 31st unless otherwise posted at the gate. Fee charged. Visitors may continue to enjoy the park during the off season by parking outside the gate and walking in during these same hours. Please be aware that facilities are closed during the off season.

Fort Knox, Maine's largest historic fort, features stunning military architecture and master granite craftsmanship. Constructed between 1844 and 1864 by master craftsmen and never fully completed, this is an unaltered example of a large mid-19th century granite coastal fortification. It is also New England's finest unmodified specimen of military architecture of the period.

The fort was strategically located on the narrows of the Penobscot River to protect the river valley from naval attack. Although it never saw combat, Fort Knox was garrisoned during the Civil and Spanish American Wars.

Fort Knox bears the distinction of being Maine's first granite fort. About 500 troops from Connecticut were stationed here during the Spanish-American War. They lived outside the main fort structure in large tents. Today, visitors can stroll the grounds of this great fort and learn about the rich history of the troops who served to protect American interests during the 1800s.

The Land and Water Conservation Fund contributed to this State Park. Learn more about LWCF.

For a geologic tour near the area visit Geology of the US Route 1/State Route 3 Roadcut - Penobscot Narrows Bridge approach.

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  • Self-guided trail

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Consider lending a hand. Contact us if you would like to help with stewardship or maintenance work.

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Services and Facilities

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Prospect, Maine

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current fees
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Fort Knox State Historic Site
711 Fort Knox Rd.
Prospect, ME 04981
(207) 469-6553


download Brochure with map (1MB/PDF)

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Directions and Parking

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On Route 174, just off U.S. Route 1 west of the Waldo-Hancock Bridge

Relevant Contacts

Fort Knox Website
Fort Knox website by the Friends of Fort Knox

Maine Office of Tourism

Email Fort Knox
Email the Friends of Fort Knox about the site.