Additional bus companies, listed as existing during 1930's, are mentioned in the WPA American Guide Series of state guidebooks.
City Bus Co. - city service, coexisted with Capitol City Bus Line.
B. & B. Bus Line - served Minot to Sanish.
Mandan-Bismarck Bus Line - served Mandan to Bismarck.
Minot-Crosby Bus Line - existed in 1930's.
Northern Bus Lines - served Wahalla to Grand Forks.