Granville Transportation Co. - began operations in 1941, suburban served Granville.
Greenfield Lake Bus Lines - suburban served Milwaukee, Greenfield, Lake Franklin, Oak Creek, Oakwood.
Milwaukee Suburban Lines - suburban served Brookfield, Elm Grove, Butler, Wauwatosa.
New Berlin Prospect Bus Lines - served West Allis, New Berlin, Prospect, Muskego.
The availability of information from the Wisconsin Public Service Commission is more thorough, than the availability of similar information for most other states. Including for the issuance of each Certificate of Convenience and Necessity. For some bus companies listed above, a year is indicated for when that company was issued a Certificate of Convenience and Necessity.