Monessen Map
Monessen Information
Monessen
Monessen is a city in Westmoreland County, Pennsylvania, along the Monongahela River. The population was 6,876 at the 2020 census. It is the southwestern-most municipality of Westmoreland County. Steel-making was a prominent industry in Monessen, which was a Rust Belt borough in the "Mon Valley" of southwestern Pennsylvania that became a third-class city in 1921. Monessen is part of the Pittsburgh metropolitan area, the Rivers of Steel National Heritage Area, as well as the Laurel Highlands. It sits across the Monongahela from North Charleroi.