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.
Graham Bus Co. - existed in 1940's to 1950's.
Maryland-Delaware Stages - served Milford, existed in 1930's.
Short Lines - served Wilmington, operated throughout Delaware, existed in 1930's to 1950's.
South Jersey Coach Co. - existed in 1940's to 1950's.
Suburban Transportation Lines - suburban New Castle to Wilmington.
Wilmington Transit Co. - operated Wilmington to Newark, existed in 1930's.