Monongahela Valley League was an unlassified league based in Pennsylvania.
1893 Braddock, Duquesne, Homestead, Irwin, Wilkensburg, Wilmerding
1894 Braddock, Duquesne, Homestead, Wilkensburg
1905 Belle Vernon, Brownsville, Charleroi, Donora, Fayette City, Monongahela City
1909 Belle Vernon, Brownsville, Donora, Fayette City, Monongahela City, Roscoe