Monongahela or Mon Valley may refer to:

Places

*Monongahela, Pennsylvania, a city in Washington County **Monongahela Cemetery, a historic cemetery in Monongahela City, Pennsylvania **Monongahela City Bridge, spans the Monongahela River *Monongahela National Forest, a national forest in eastern West Virginia *Monongahela River, a tributary of the Ohio River **Battle of the Monongahela (9 July 1755), at the beginning of the French and Indian War *Lake Monongahela, former Proglacial lake in Pennsylvania, West Virginia, and Ohio * Monongahela Formation, a geologic group

Railways

*Monongahela Railway, a coal-hauling short line railroad in Pennsylvania and West Virginia in the United States *Monongahela Connecting Railroad, a small industrial railroad in Pittsburgh, Pennsylvania *Monongahela Freight Incline, a funicular railway that scaled Mount Washington *Monongahela Incline, a funicular located near the Smithfield Street Bridge in Pittsburgh, Pennsylvania

Other

*Monongahela (album), ''Monongahela'' (album), a 1988 album by The Oak Ridge Boys *Monongahela (fish), ''Monongahela'' (fish), a genus of prehistoric fish *''Monongahela virus'', an Orthohantavirus *Monongahela culture, a Native American group *USS Monongahela, USS ''Monongahela'', one of various ships of the United States Navy * the ''Mon Valley'', a variant name of the PATrain commuter rail service *''Monongahela'', a whaleship lost in 1853. {{disambiguation, geo