Monessen is a former steel town at the north end of the Steel Valley which is the steel manufacturing corridor along the Monongahela River, south of Pittsburgh. Monessen's population has fallen to 7,625 (2012) from a high of 20,268 in 1930. Almost nothing is left of the Pittsburgh-Wheeling mill that was central to Monessen's economy. The site has been redeveloped as an industrial park but has not had much luck attracting new tenants. Downtown Monessen is largely vacant but still retains many of it's historic buildings. Monessen's residential neighborhoods are high on a bluff over downtown and the former mill site. The residential and commercial industrial areas are connected with steps that run down the hill through a park. Most of Monessen was built from 1900 to 1920.