Beginning in 1921, intrastate bus service was regulated by the Oregon Public Utility Commission. Information could not be located, regarding the issuance of Certificates of Convenience and Necessity for bus service. But the January 1923 issue of the publication "Bus Transportation" included a table listing the bus routes in existence in Oregon.
Not listed are city bus routes, along with bus routes of a suburban nature operating strictly within one county.
This information does not include the actual bus companies operating most of the routes. For most routes it was not possible, to establish how these companies became part of the Greyhound or other larger bus companies.
The earliest main bus routes in Oregon operated from Portland, south into California and east along the Columbia River into Idaho. Route introduced in 1921 from Portland south to Sacramento CA, by Pickwick Stages which later became part of Pacific Greyhound Lines. And route introduced in 1921 from Portland east to Pendleton by Columbia Stages, sold in 1926 to Columbia Gorge Motor Coach Co., and became part of Overland Greyhound Lines.
Portland-Newberg-McMinnville Portland-Hillsboro-McMinnville Portland-Salem Portland-Tillamook Portland-Seaside Portland-Hood River Portland-California State Line Salem-Mill City Salem-Albany Albany-Corvallis Eugene-Corvallis Eugene-Cottage Grove Eugene-Roseburg Grants Pass-Roseburg Grants Pass-Waldo Medford-Ashland Medford-Grants Pass Eugene-Bellknap Alsea-Corvallis Lebanon-Cascadia The Dalles-Dufur Sheridan-McMinnville Astoria-Seaside Scappoose-Portland Medford-Klamath Falls Klamath Falls-Chiloquin Klamath Falls-Crater Lake Klamath Falls-Lakeview Pilot Rock-Pendleton Pendleton-Washington State Line Umatilla-Pendleton Weston-Pendleton Union-La Grande Crane-Burns Baker-Cornucopia Coquille-Marshfield Coquille-Myrtle Point Bandon-Port Orford Cannon Beach-Seaside Bend-Burns Bend-Klamath Falls Vale-Ontario Portland-Government Camp Portland-Sandy Portland-Silverton Hood River-The Dalles Hood River-Parkdale Baker-La Grande Hoaglin-Roseburg