Point Marion Lock and Dam, previously known as Lock and Dam Number 8, is one of nine navigational structures on the Monongahela River between Pittsburgh, Pennsylvania and Fairmont, West Virginia. Maintained and built by the U.S. Army Corps of Engineers, the gated dam forms an upstream pool that is 11.2 miles (18.0 km) long, stretching to the base of the Morgantown Lock and Dam. It is located at river mile 90.5.