Additional bus companies, listed as existing during 1930's, are mentioned in the WPA American Guide Series of state guidebooks.
Additional information is from the "Opinions and Orders" from the Illinois Commerce Commission.
Central West Motor Stages - began operations in 1942, connecting Chicago with the Great Lakes Naval Training Station.
Chicago Ridge Transit System - as of 1952, operated 2 buses in Worth and Chicago Ridge and southwest suburbs, with route on 111th St. west of Pulaski. Probably ceased operations in 1960's.
City Transportation System - operated city service within Zion from 1946 into 1950's.
Fox Valley Coach Lines - introduced route in 1923 from Elgin to Dundee, Crystal Lake, and Woodstock, extended to Harvard in 1927. Route added in 1947 from Crystal Lake to Marengo and Rockford.
Eagle Bus Lines - began operations in 1947, connecting Chicago with various race tracks.
Franklin Park Bus Co. - began operations in 1927, operating via Grand Ave. from Harlem Ave. to Franklin Park.
Gold Star Line - began operations in 1924 with route which eventually became part of South Suburban Safeway Lines and Pace route #353, along with local service introduced in Chicago Heights in 1927. Later primarily operated from Joliet to Frankfort, Chicago Heights, and Hammond. Route introduced in 1924 by Chicago Heights & Joliet Transportation Co. Some service sold to South Suburban Safeway Lines in 1950's, through service operated until 1966.
Harvel Motor Coach Co. - began operations in 1946 with five routes based at Arlington Heights railroad station, primarily during rush hours and with school trips. As of 1952 owned 2 buses. Two routes sold to United Motor Coach Co. in early 1960's, discontinued in early 1970's.
Highland Park Coach Lines - operated between Highland Park and Deerfield. Controlled by Leyden Motor Coach Co.
Illiana Motor Bus Co. - in 1925 and 1926 operated two bus routes, connecting Calumet City with the Ford Motor Co. plant in Hegewisch.
J. M. & K. Transportation Co. - service between Joliet and Kankakee introduced in 1924 by Kankakee Joliet & Pontiac Bus & Transfer Line, renamed in 1927 to Illinois Roadway Lines. From 1929 to 1933, Joliet Plainfield & Aurora Transportation Co. operated the route. From 1939 to 1951, Joliet Manhattan & Kankakee Transportation Co. operated the route.
Joliet-Aurora Transit Lines - operated between its namesake cities, beginning probably in the 1930's as Joliet Plainfield & Aurora Transportation Co. Around 1950 became Joliet-Aurora Transit Lines. In 1968 acquired the Aurora-Elgin Bus Line from National City Lines, with the original Joliet-Aurora operation discontinued around 1969. Ceased operations in 1973, with Aurora-Elgin route turned over to Elgin Department of Transportation.
La Grange & La Grange Park Transit Co. - began operations in 1949 by acquiring local lines from Chicago & West Towns Railway. Operated 22 different routes. As of 1952 owned 4 buses, operated into 1970's.
Merkle Service Co. - began operations in 1927, with route from 87th St. and Ashland Ave. to Maria Cemetery near 91st St.
Ordnance Plant Bus Service - began operations in 1942, assuming route introduced previous year by Joliet City Lines, connecting Joliet with Ordnance Plant to the south.
Round Lake Transit System - as of 1952, operated 5 buses in Round Lake.
Safety Transportation Co. - as of 1952, operated between Chicago and Evanston, Glenview, Algonquin, Downers Grove. Also operated city service in Downers Grove.
Station to Lake Bus Line - began operations in 1927, providing local service in Crystal Lake.
W.A.F. Transportation Co. - began operations in 1946 with route from Woodstock through McHenry to Crystal Lake, introduced additional route in 1947 from McHenry to Crystal Lake via Wauconda.
Willey Coach Lines - from 1937 to 1939 operated route from Wheaton to West Chicago.