Additional bus companies, listed as existing during additional years or decades, are mentioned in old City Directories, and in the WPA American Guide Series of state guidebooks.
California Bus Service - served Richeyville, Brownsville, Newell, Fayette City, Belle Vernon.
Patsch Auto Bus Co. - suburban based in Houston PA, no further information.
Union Transit Co. - served Waynesburg to Pt. Marion and Masontown.