Additional bus companies, listed as existing during 1930's, are mentioned in the WPA American Guide Series of state guidebooks.
Suburban and interurban bus companies listed in the Russell's Official National Motor Coach Guide, which was primarily a resource for intercity bus lines.
Wabash Valley Coach Co. (to Vincennes and Evansville, until 1974)
Wabash Valley Lines (to Casey IL, until 1953)
Western Indiana Coach (to Crawfordsville, until 1969)
Western Motor Lines (to Paris IL, until 1952)
R. F. Johnson Bus Line - served Terre Haute, Ashboro, Clay City, Coal City, Worthington, Linton, Crane.
National Motor Transit Co. - existed in 1930's.