1922 - The Milwaukee Electric Railway & Light Company forms subsidiary Wisconsin Motor Bus Lines to operate buses, and introduces bus service between Milwaukee and West Bend. Boulevard Transit Co. introduces bus service between Milwaukee and Hartford, shortly after which Wisconsin Motor Bus Lines acquires Boulevard Transit Co. Wisconsin Motor Bus Lines also acquires Eastern Wisconsin Transportation Co., which had recently introduced bus service from Milwaukee beyond West Bend to Fond Du Lac.
1923 - Bus route from Milwaukee to Hartford extended to Beaver Dam.
1924 - Additional bus route to Beaver Dam introduced, connecting with Milwaukee to Fond Du Lac route at Theresa, and later extended south of Beaver Dam to Watertown.
1925 - Theresa-Beaver Dam-Watertown bus route discontinued.
1926 - Wisconsin Motor Bus Lines acquires Gray Motor Stage Line, operating from Beaver Dam through Watertown to Janesville, enabling resumption of a portion of route discontinued previous year. Service also resumed over portion of route west of Theresa, to Mayville. Service discontinued between Hartford and Beaver Dam. American Coach Co. introduces bus service between Milwaukee and Green Bay.
1927 - Wisconsin Motor Bus Lines acquires American Coach Co.
1930 - Bus routes acquired from Wisconsin Power & Light Co. between Sheboygan and Green Bay, from Iron River Transportation Co. between Green Bay and Iron Mountain, and introduced between Sheboygan and Appleton, connecting with railway at Sheboygan.
1931 - Bus route between Green Bay and Iron Mountain sold to Gray Transportation Co.
1933 - Bus route between Sheboygan and Appleton sold to Roy Vandenburg.
1934 - Wisconsin Motor Bus Lines ceases to be a separate subsidiary of The Milwaukee Electric Railway & Light Company.
1936 - Bus route between Sheboygan and Green Bay sold to Green Bay Stages.
1937 - Bus service between Beaver Dam and Janesville, and between Milwaukee and Fond Du Lac sold to Northland Greyhound Lines. The Milwaukee Electric Railway & Light Company would be left with no bus service north or northwest of Milwaukee.
1938 - Northland Greyhound Lines sells Beaver Dam-Janesville route. During 1940's, route would be operated by Swenson Coach Lines.
1948 - Northland Greyhound Lines acquires Sheboygan-Green Bay route from Green Bay Stages, and forms through route from Milwaukee over segments which had replaced interurban railway between Milwaukee and Sheboygan.