Additional bus companies, listed as existing during 1930's, are mentioned in the WPA American Guide Series of state guidebooks.
Crawford Line - existed in 1930's.
Litten & Litten Motor Lines - based in Knoxville, served Brunswick, Hagerstown.
Kirwan's - existed in 1930's, served Cambridge.
Shore Bus Lines - served Ocean City and Fenwick Island.
West Side Transit Lines - suburban served Salisbury, Crisfield.
Bainbridge Bus Co. - served Port Deposit, Perryville, Bainbridge, Havre de Grace.
Hill's Jitney Service - suburban served Elkton, Chesapeake City, Conowingo, Newark DE and vicinity.
Inter-City Lines - served Havre de Grace, Aberdeen, Edgewood, Bainbridge, Perryville, Perry Point, Lancaster PA.
Bus companies operating over longer distances than the above suburban and interurban companies, but not listed in the Russell's Guide.
Maryland Motor Lines - intercity served Baltimore, Towson, Jacksonville, Stewartstown PA, Loganville PA, York PA.