Maine's Fort Knox Park: A Living Lesson

One of America's great architectural, engineering, and construction legacies is a set of coastal defense fortifications built during the mid-1800s, the so-called "Third System," built largely under the supervision of U.S. Army engineer Joseph Totten. Strung along the Atlantic coastline from Fort Knox in Downeast Maine to Fort Jefferson on the Dry Tortugas south of Key West, Florida, and around the Gulf Coast to Fort Livingston on Barataria Island in Louisiana, the forts in their day represented the state-of-the-art in defense of land against invasion from the sea. Among other attributes, the 42 "Third System" forts (including two West Coast examples in San Francisco) are an early example of a vegetated roof system. Each fort was topped with deep soil, intended to protect against naval barrages — but also effective in tempering the extremes of climate, whether in frozen Maine or sub-tropical Florida. Last year, Coastal Connection took a trip to Fort Jefferson, 90 miles out in the Gulf of Mexico (" Restoring an Island Fortress Brick by Brick ," May 24, 2011). This spring, we visited the northernmost fort in the system: Fort Knox, sited across the Penobscot River from Bucksport in Prospect, Maine. In an era where the U.S. and Britain were fiercely contesting control of the region, Fort Knox was built to command a strategic bend in the Penobscot River, the gateway to the northern timberlands of Maine and a water highway from the coast to the city of Bangor, a lumber-producing powerhouse in the first half of the 19th century. The fort is now a Maine State Park , open to the public during daylight hours. Fort Jefferson was built entirely of brick, brought to the fort's coral-island site by boat from Florida, or, during the Civil War, from New York. But Fort Knox (named after Revolutionary War General Henry Knox, who served as the nation's first Secretary of War) is constructed of huge blocks of local granite, quarried on nearby Mount Waldo, five miles upriver from the fort. The forts do share many basic features, from the design of their gun placements under brick-vault ceilings, to their earth-sheltered roofs. But Fort Knox had to conform to a sloped site at the top of a river bluff, and its design, as well as its stonework, display an interesting creative adaptation to that problem. From the stepped rifle embrasures along the path at the base of the fort's wall, to the carefully crafted junctures where different-sized arches meet, to the complex vaulted brickwork at the step-down passage doors between rooms in the enlisted men's quarters, the fort's details show an investment, not just of government money, but of refined architectural intelligence and expert craftsmanship. Stepped rifle embrasures follow the slope of a path along the fort's northern wall. Fort Knox differs in some structural details from other forts in the Third System. But gun placements were standardized: Any trained gun crew could have stepped up and fired this cannon at a moment's notice. Form matches function in the carefully cut stonework at the junction between two different-sized arches, as the fort's wall and its vaults step down the slope of the river bluff. Different times, different technologies: In this view to the south at the fort's topmost terrace, the irregular pattern of sloped granite wall caps, cut and placed by expert stonemasons in the mid-1800s, gives way to a vista of the newly built Penobscot Narrows Bridge (finished in 2006) and the now-retired Waldo-Hancock bridge, completed in 1931. A view to the north from atop the earth cap shows the Verso Paper mill on the east bank of the Penobscot in the town of Bucksport. Fort Knox, and the chain of coastal forts like it, saw little if any action in war. But this may be a testament to their success — the supreme accomplishment of a military deterrent, after all, is to prevent the war from ever occurring. Now, like outmoded missile silos in North Dakota, the forts stand empty and quiet. But they're well worth a visit — for anyone who cares about architecture and craftsmanship, they're a living lesson in design, as well as in history. For the rest of Coastal Connection's photo tour of Fort Knox, click here (" Fort Knox State Park, Prospect, Maine " - photos by Ted Cushman).