Four Hundred Feet Above the Penobscot
The Penobscot Narrows Bridge Observatory rises 420 feet above the Penobscot River in Prospect, Maine. Built into the western pylon of a cable-stayed bridge, it is the tallest public bridge observatory in the world and the tallest occupied structure in Maine. An elevator ride lasting about a minute delivers you to an enclosed observation deck with 360-degree views of Penobscot Bay, the Camden Hills, the river valley, and on clear days, Cadillac Mountain in Acadia National Park roughly 40 miles to the east.
The bridge itself opened in December 2006, replacing the deteriorating Waldo-Hancock Bridge that had spanned the narrows since 1931. Engineers incorporated the observatory into the design from the start, making it the first bridge observation tower in the United States. The 2,120-foot cable-stayed bridge carries US Route 1 and Route 3 over the Penobscot River, connecting Verona Island to Prospect.
At the base of the observatory sits Fort Knox, a massive granite fortification built between 1844 and 1869 to defend the Penobscot River valley. The fort and the observatory share a parking lot and a combined admission ticket, making this one of the more unusual pairings of historic site and modern engineering in New England.
The Observatory Experience
You enter the observatory through the Fort Knox visitors center, where you pick up your ticket. A short walk brings you to the base of the bridge pylon, and then you ride Maine’s fastest elevator up 42 stories to the observation deck.
The deck is fully enclosed with large windows on all sides. Interpretive panels identify landmarks visible from each direction: the Camden Hills to the southwest, Penobscot Bay opening to the ocean, Bucksport and its paper mill site across the river, and the forested highlands stretching north toward Katahdin. On a clear day the views extend for 50 miles or more.
The experience takes about 30 to 45 minutes for the observatory itself. The elevator holds a limited number of people, so there can be a short wait during busy times, but the line moves quickly.
Fort Knox
Do not skip the fort. Fort Knox is one of the best-preserved granite forts on the Eastern Seaboard, and it is far more interesting than you might expect. Construction began in 1844 during tensions with Britain over the Maine-Canada border (the Aroostook War) and continued through the Civil War era, though the fort was never attacked.
The fort features granite walls up to 40 feet thick, spiral staircases, underground magazines, a hot-shot furnace for heating cannonballs, and a network of tunnels and passageways you can explore on your own. Bring a flashlight for the interior chambers. The masonry work is impressive, and the scale of the place is surprising for a fort in rural Maine.
The Friends of Fort Knox host events throughout the season, including a popular Fright at the Fort Halloween event in October.
When to Go
Summer
Peak season with full hours (9am-6pm July-August). Warm weather for exploring Fort Knox. Busiest on weekends.
Fall
Clearest views from the observatory. Foliage color in the surrounding hills. Extended to 5pm closing. Fright at the Fort in October.
Spring
Opens May 1. Fewer crowds, pleasant weather for fort exploration. Views can be hazy.
Winter
The observatory and fort close November 1 through April 30.
Getting There
The observatory and Fort Knox are located off Route 1 in Prospect, on the west bank of the Penobscot River. From Bangor, take Route 1A south to Prospect, about 30 minutes. From Portland, follow I-95 north to Augusta, then Route 3 east toward Belfast, and Route 1 north. The drive takes about 2 hours and 15 minutes.
The entrance is well-signed from Route 1. The parking lot is at Fort Knox, and the observatory entrance is through the fort’s visitors center.
GPS coordinates: 44.5667, -68.7978
FAQ
How tall is the Penobscot Narrows Bridge Observatory?
The observatory is 420 feet above the river, making it the tallest public bridge observatory in the world and the tallest occupied structure in Maine.
How much does the Penobscot Narrows Observatory cost?
A combined ticket for the observatory and Fort Knox costs $9 for adult non-residents, $7 for Maine residents, and $3 for children ages 5-11. Children under 5 are free.
When is the observatory open?
May 1 through October 31. Hours are 9am to 5pm, extended to 6pm in July and August. It is closed November through April.
Are dogs allowed at the observatory?
Dogs are not allowed in the observatory elevator or observation deck. They are allowed on leash at Fort Knox grounds.
How long should I plan for a visit?
Plan 2 to 3 hours total: about 30-45 minutes for the observatory, and 1 to 2 hours for Fort Knox. The fort is extensive and worth exploring thoroughly.
