Fort Knox and Penobscot Narrows Observatory
See main listingThis 19th-century granite fort sits near Prospect, about an hour west of Bar Harbor on Route 1. The main draw for most visitors is the modern Penobscot Narrows Bridge Observatory, a 420-foot tower offering sweeping views of the Penobscot River valley. You can buy a ticket for the fort alone (about $6.50 for out-of-state visitors) or combine it with the observation tower.
The fort itself is well-preserved and dog-friendly, so you can bring your pup to explore the grounds. Staff are welcoming, and there's a gift shop on site. The site works well if you're passing through on Route 1 or making a day trip from the coast.









