There are 17 historic wooden covered bridges in the U.S. State of West Virginia. Only three of these bridges were built before 1870 and they are the three longest in the state. Each uses a standard truss design, braced with the Burr Arch. No one-truss design dominates in the state. The bridges are located in three general areas. In the south, in Monroe and Greenbrier counties, there are about a half dozen bridges within an easy drive of one another. To the north around Philippi is another group of bridges, including the historic Philippi Covered Bridge, which is the longest (285 feet (87 m)) and an important part of state history for its associations with the American Civil War.