1900-1906 - Michigan Traction Co. (Battle Creek-Kalamazoo)
1903-1906 - Jackson & Battle Creek Traction Co.
1903-1904 - Lansing St. Johns & St. Louis Railway Co.
1904-1906 - Lansing & Suburban Traction Co.
1905-1908 - Detroit Flint & Saginaw Railway Co. (Saginaw-Frankenmuth)
1908-1915 - Saginaw & Flint Railway
1906-1923 - Michigan United Railways Co.
1923-1929 - Michigan Electric Railway Co.
Jackson-Battle Creek (constructed 1903, discontinued 1928)
Battle Creek-Kalamazoo (constructed 1900, discontinued 1928)
Jackson-Lansing (constructed 1909, discontinued 1929)
Lansing-St. Johns (electrified 1904, discontinued 1929)
Lansing-Owosso (constructed 1911, discontinued 1929)
Saginaw-Frankenmuth (constructed 1905, discontinued 1927)
Saginaw-Flint (constructed 1909, discontinued 1929)
Replacement bus companies:
Southern Michigan Transportation Co. (1920's-1935)
Eastern Michigan Motorbuses (1935-1941)
Great Lakes Greyhound Lines (after 1941)
MICHIGAN RAILROAD CO.
1915-1919 - Michigan Railway Co.
1914-1919 - Saginaw Bay-City Railway Co.
1919-1928 - Michigan Railroad Co.
Saginaw-Bay City (constructed 1914, discontinued 1929)
Kalamazoo-Grand Rapids (constructed 1915, discontinued 1928)
Battle Creek-Allegan (electrified 1915, discontinued 1928)
Information on how the Michigan United Railway bus operations evolved into part of the Greyhound bus system.
Schedules of interurban lines in Michigan, from the August 1923 Russell's Official Eastern States Railway Guide.