Washington Motor Coach Co.
Incorporated in 1924, renamed in 1926 from Yakima Northern Stages.
Operated from Yakima to Ellensburg.
Yakima Motor Coach Co.
Operated from Yakima to Portland.
Olympic Peninsula Motor Coach Co.
Operated from Seattle to Port Ludlow.
Spokane-Butte Motor Coach Co.
Began operations in 1933
Operated from Spokane to Butte MT.
The above companies were merged in 1937 into Washington Motor Coach Co.
The 1937 merger, along with earlier acquisitions and extensions, completed formation of a system from Seattle and Portland to Spokane and Butte MT.
Northwest Greyhound Lines subsequently acquired the following company:
Auto Interurban Co.
Incorporated in 1920, and over the years gradually sold routes to various Greyhound predecessors. Acquired in 1956.
Operated routes radiating from Spokane.
Northwest Greyhound Lines consolidated in 1957 into Western Division of Greyhound.