A listing and history of the many and varied streetcar and electric interurban companies that formed and merged over the years.
Barnes Heights & Cornell Mountain Railway Company (1890–1895)
City & Suburban Railway Company (1891–1904)
City & West Portland Park Motor Company (1889–1901)
City Cable Company (1892–1894)
Clackamas Southern Railway Company (1908–1914)
East Portland Railway Company (1873–???)
East Portland Railway Company (1882–???)
East Side Railway Company (1891–1901)
First Street Railway Company* (1893–1900)
Kenton Traction Company (1909–1933)
Metropolitan Railroad Company (1896–1900)
Metropolitan Railway Company (1889–1892)
Mount Hood Railway & Power Company (1906–1912)
Mount Tabor Street Railway Company (1889–1892)
Multnomah Railway Company (1882–1888)
Multnomah Central Railway Company (1912–1915)