Covered bridge over Deer Creek

A photograph of a covered bridge over Deer Creek, north of Chillicothe on State Route 104. A caption on the back reads "Bridge Over Deer Creek." Ohio has a large number of covered bridges, falling second only to Pennsylvania in quantity. Within the state of Ohio, Fairfield County and Ashtabula County lead the state in containing the most original covered bridges. Most covered bridges in the U.S. were built between 1825 and 1875, with the first Ohio covered bridge built in 1829 in Eaton in Preble County. Bridges were covered to protect the structural wooden tresses from the elements, giving the bridges a longer life span of approximately 100 years as opposed to 20 years for an uncovered bridge. At one point in time, Ohio had approximately 3, 500 covered bridges, but that number has diminished to approximately 138 covered bridges today