North Seattle Cable Railway Co. - incorporated 1890, leased by First Avenue Railway Co.
Grant Street Electric Railway Co. - incorporated 1891, sold 1900 to Seattle Electric Co.
Green Lake Electric Railway Co. - incorporated 1889, sold 1900 to Seattle Electric Co.
Madison Street Cable Railway Co. - incorporated 1889, sold 1900 to Seattle Electric Co.
South Seattle Cable Railway Co. - incorporated 1889, controlled by Madison Street Cable Railway, sold 1891 to Seattle Electric Railway & Motor Co., abandoned 1895.
Rainier Power & Railway Co. - incorporated 1889, sold 1895 to Third Street & Suburban Railway, sold 1900 to Seattle Electric Co.
Seattle Central Railway Co. - incorporated 1900, sold 1903 to Seattle Electric Co.
Seattle City Railway Co. - incorporated 1887 as Seattle Construction Co., sold 1890 to Seattle City Railway Co., sold 1901 to Seattle Railway Co., sold 1901 to Seattle Electric Co.
Seattle Street Railway Co. - incorporated 1884, sold 1889 to Seattle Electric Railway & Power Co., sold 1891 to Seattle Consolidated Street Railway, sold 1896 to Seattle Traction Co., sold 1900 to Seattle Electric Co.
West Street Lake Union & Park Transit Co, - incorporated 1888, sold 1889 to Seattle Electric Railway & Power Co.
Union Trunk Line - incorporated 1890, sold 1900 to Seattle Electric Co.
West Street & North End Electric Railway Co. - incorporated 1890, sold 1900 to Seattle Electric Co.
Woodland Park Electric Railway - incorporated 1890, sold 1900 to Seattle Electric Co.
West Seattle Cable Railway Co. - suspended operations 1897.
Highland Park & Lake Burien Railway - incorporated 1911, sold 1913 to Seattle Municipal Railway.
Loyal Railway Co. - incorporated 1906, sold 1907 to Loyal Heights Electric Railway, sold 1918 to Seattle Municipal Railway.
Everett & Interurban Railway - incorporated 1902, sold 1907 to Seattle-Everett Interurban Railway Co., sold 1910 to Seattle-Everett Traction Co., sold 1912 to Pacific Northwest Traction Co., trackage in city sold 1920 to Seattle Municipal Railway.
Rainier Ave. Electric Railway Co. - incorporated 1889, sold 1895 to Seattle & Rainer Beach Railway, sold 1899 to Seattle & Renton Railway Co., sold 1903 to Seattle Renton & Southern Railway, sold 1916 to Seattle & Rainer Valley Railway, abandoned 1937 and replaced with Seattle Municipal Railway buses.