Fort Knox and the Penobscot Narrows Observatory

740 Fort Knox Road

Located on the west bank of the Penobscot River in Prospect, Maine, in an area known as the Penobscot Narrows, Fort Knox is one of the best preserved fortifications on the New England seacoast. The Fort has many architectural features present only to itself, as well as a rich history behind its cannon batteries.

Maine was repeatedly involved in northeast border disputes with British Canada, and the area between Castine and the rich lumber city of Bangor was invaded and occupied by the British during the American Revolution and the War of 1812. Despite the Webster-Ashburton Treaty of 1842, Fort Knox was established in 1844 to protect the Penobscot River valley against a possible future British naval incursion.

The Fort was designed by Chief Engineer Joseph Totten with a number of other engineers serving as superintendents of construction from 1844 - 1869, among them Isaac Ingalls Stevens and Thomas L. Casey. The Fort was named for Major General Henry Knox, America's first Secretary of War, who was born in Boston but retired to Thomaston, Maine in 1796. The Fort garrisoned its first troops from 1863 to 1866. These troops were mostly volunteers undergoing training before being sent to their active posts and included members of the celebrated 20th Maine. Troops were also briefly stationed at the Fort during the Spanish American war in 1898, but never saw military action.


Kristi Aslin

Thursday, Oct. 12, 2017

Great place to see the fall colors. The observatory is very cool. Rises to 400 fee with 360 degree views up and down the river. The fort is such an amazing structure. Great location too.

Dave Shapiro

Sunday, Oct. 8, 2017

Very interesting old fort established to protect Maine from a British invasion. You can wander throughout the fort and there is a lot of explanation available. Views of the interior and exterior are excellent. Bring a flashlight, some areas are very dark. The vast majority of the fort is handicap accessible however, there are a couple of spots that would be difficult. (Spiral staircase.). Views of the river and the bridge are excellent.

Andrew Bartels

Tuesday, Aug. 29, 2017

Well worth a stop. The observatory on the Bridge is a must see. Easy parking and access. The Fort is fun especially with kids. Don't miss out on the 69 steps which take you down to the rivers edge. The Fort and Observatory are included in the price of admission. We stopped primarily to see the bridge observatory not even realizing the Fort was there.

p fb

Wednesday, Nov. 1, 2017

spent about 3 hours here at this interesting. well presented, significant historic fort. Very family/child inspired exhibits. Highly recommended, excellent time/$ value.. Don't miss this stop when visiting Maine

Christa Walter

Tuesday, Sep. 26, 2017

Well, there are 4 observation bridge towers in the world, the one in little old Prospect Maine is not only the tallest, it's the only one in this Hemisphere. Worth the stop to take the ride to the top. Handicap accessible they have 2 wheelchairs that can take you to the very top one at a time in a lift. I took my parents, both unable to walk and they loved it. Views are spectacular and on a clear day you can see over 70 miles away.