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Historic timber bridges enclosed by a roof and siding, protecting the wooden structure from the elements.
Covered bridges hold a special place in American history and culture. These charming structures, most commonly timber truss bridges enclosed by a roof and wooden siding, were once ubiquitous across the American landscape. The covering was not for the comfort of travelers but to protect the structural timber from rain, snow, and sun, which could cause the wood to rot and deteriorate within 10-20 years. A well-covered bridge could last 80 years or more.
At their peak in the mid-1800s, there were an estimated 12,000 to 14,000 covered bridges in the United States. Today, fewer than 750 remain, preserved as historic landmarks and beloved tourist attractions. Pennsylvania and Vermont have the most surviving covered bridges, and many states have active preservation societies dedicated to their maintenance.
Covered bridges are typically built using one of several timber truss designs: the Town lattice (crisscrossing planks), the Burr arch-truss (combining an arch with a truss), the Howe truss, or the queenpost truss. Each builder often had a preferred design, and regional patterns developed across the country. Today, they represent an important chapter in American engineering and cultural history.
Structurally, a covered bridge is a timber truss bridge with a protective enclosure. The truss does the actual work of spanning the gap, using the same principles as any truss bridge: interconnected triangles distribute loads through tension and compression in individual members. The Town lattice truss uses a web of overlapping diagonal planks pinned together at their intersections. The Burr arch-truss combines a kingpost or queenpost truss with a superimposed arch for added strength. The covering (roof and siding) serves purely as protection for the structural wood beneath, keeping rain and snow off the critical joints and members. The roof is typically a simple gable structure, and the siding may include windows or openings for ventilation. The floor system consists of transverse floor beams resting on the bottom chords of the trusses, with longitudinal planking forming the road surface.
Vermont's covered bridges were historically known as "kissing bridges" because the dark, enclosed passage gave courting couples a brief moment of privacy during horse-and-buggy days. Some covered bridges even have signs encouraging the tradition.
Cornish-Windsor Bridge (New Hampshire/Vermont, longest in US at 460 ft)
Bridges of Madison County (Iowa)
Blenheim Bridge (New York, destroyed by Hurricane Irene, rebuilt)
Hogback Covered Bridge (Iowa)
West Cornwall Covered Bridge (Connecticut)
Sachs Covered Bridge (Gettysburg, Pennsylvania)
Iconic bridges with a deck hung from cables draped over tall towers, capable of spanning enormous distances.
Modern bridges where cables run directly from towers to the deck, creating a dramatic fan or harp pattern.
One of the oldest bridge forms, using a curved structure to transfer loads outward to abutments at each end.
Bridges built from interconnected triangular elements, combining strength and material efficiency.