St. Clairsville Belmont CountyOhio www.stclairsville.com Map Population 5,085 (2020)Type CityArea 2.42 sq mi (6.27 km²), 0.02 sq mi waterGovernment CITY OF ST CLAIRSVILLEGovernment office PO BOX 537, SAINT CLAIRSVILLE, OH 43950