The tri-level, glass-walled Penobscot Narrows Bridge Observatory caps the 447-foot-high west tower, delivering jaw-dropping views over Penobscot Bay, the Camden Hills, Mount Desert Island, and even Katahdin, the state’s highest peak.
But be forewarned: The tower’s elevator zips up 40 stories before opening to floor-to-ceiling glass windows framing the Penobscot River. It’s shocking for most and terrifying for those with a fear of heights. Continue to the top level for the best head-swiveling views. Placards label the various mountains and lakes within sight. (Updated May 2, 2025)
Access to the observatory is through Fort Knox, a 125-acre state historic site built to protect the upper Penobscot River and named for Major General Henry Knox, George Washington’s first secretary of war. Although construction on the sprawling granite fort began in 1844, it was never finished and never saw battle. “It was very well thought out and planned, and that may have been its best defense,” according to a guide.
The fort overlooks the river and Bucksport. Bring a picnic to enjoy the views and a flashlight to explore the fort’s underground passages.
Tickets, including the fort, range from $3 to $9.50. The fort, dating from 1844, is beautifully restored and a great place for a picnic. It’s also the site of frequent re-enactments and other special events, ranging from a Renaissance Fair to Fright at the Fort, a Halloween spooktacular.
Penobscot Narrows Bridge fun facts
- Maine’s first cable-stay bridge (similar to Boston’s Zakim) opened in 2007, replacing the 75-year-old Waldo Hancock suspension bridge. It’s twice as high as the original.
- The Washington Monument, built around the same time as Fork Knox, inspired the designers, who used the same Maine granite as the monument’s foundation.
- The observatory is the world’s tallest bridge observatory and the only one in the United States.
- It usually takes a decade to construct a bridge of this type, but his one was completed in 3.5 years.
- The only gold in this Fort Knox is pyrite, a.k.a. Fool’s Gold.
