A covered bridge is a bridge with enclosed sides and a roof, often accommodating only a single lane of traffic. Most covered bridges are wooden; some newer ones are concrete or metal with glass sides. Mainly associated with the 19th century, covered bridges often serve as prominent local landmarks and have long attracted the attention of historic preservationists.

The enclosure acts as weather protection over the working part of the structure. For example, a bridge built entirely out of wood, without any protective coating, may last 10 to 15 years. Builders discovered that if the bridge's underpinnings were protected with a roof, the bridge could stand for 70 or even 80 years. Existing covered bridges have been renovated using concrete footings and steel trusses to hold additional weight and to replace the original support timbers. Some covered bridges, such as the ones in Newton Falls, Ohio and Elizabethton, Tennessee, also feature an integrated covered walkway.