The Puget Sound Power & Light Company records are arranged in accordance with the following series arrangement:

Series 1. Baker Estates, 1903-1907

Series 2. Bellingham and Skagit Railway Company, 1910-1912

Series 3. Bellingham Bay & Eastern Railroad Company 1892-1899

Series 4. Bellingham Bay Electric Street Railway Company, 1890-1912

Series 5. Bellingham Bay Gas Company 1890-1902

Series 6. Bellingham Bay Gas and Railway Company, 1890-1891; 1896

Series 7. City Transport Company, 1922-1926

Series 8. Columbia Improvement Company, 1903-1905

Series 9. Edison General Electric Company, undated.

Series 10. Everett Railway and Electric Company/ Everett Railway and Light Company, 1893-1907

Series 11. Everett Railway, Light and Water Company, 1896-1924

Series 12. Fairhaven and New Whatcom Railway Company, 1891-1897

Series 13. Fairhaven and Southern Railroad Company, 1890-1891

Series 14. Fairhaven Electric Light Power and Motor Company, 1891; 1900-1901

Series 15. First Avenue Railway Company, 1898-1901

Series 16. Front Street Cable Railway Company, 1888-1898

Series 17. Grant Street Electric Railway Company, 1891-1900

Series 18. Green Lake Electric Railway Company, 1889-1902

Series 19. Lake Whatcom Electric Railway Company, 1892

Series 20. Lynden Electric Railway and Improvement Company, 1901-1906; 1917

Series 21. Madison Street Cable Railway Company, 1889-1900

Series 22. Northern Railway and Improvement Company, 1898-1903

Series 23. North Seattle Cable Railway Company, 1889-1899

Series 24. Pacific Coast Power Company, 1904; 1910-1911

Series 25. Pacific Northwest Traction Company, 1911-1930

Series 26. Pacific Traction Company, 1909-1929

Series 27. Puget Sound Bus Company, 1915-1923

Series 28. Puget Sound Electric Railway Company, 1903-c. 1960s (1903-1929)

Series 29. Puget Sound International Railway and Power Company, 1907-1930

Series 30. Puget Sound Power and Light Company, ca. 1980s

Series 31. Renton Coal Company, 1901-1924

Series 32. Renton Co-operative Coal Company, 1895-1901

Series 33. Renton Mine and Renton Mines Association, 1902-1919

Series 34. Seattle Central Railway Company, 1899-1903

Series 35. Seattle Consolidated Street Railway Company, 1888-1899

Series 36. Seattle Electric Company, 1894-1922

Series 37. Seattle Motor Livery Company, 1902-1912

Series 38. Seattle Railway and Seattle City Railway Company, 1890-1922

Series 39. Seattle-Tacoma Interurban Railway & Seattle-Tacoma Railway Co., 1899-1912

Series 40. Seattle Tacoma Power Company, 1905-1906

Series 41. Seattle-Tacoma Union Stage Lines, 1921-1923

Series 42. Seattle Traction Company & Seattle-Everett Traction Company, 1897-1911

Series 43. South Seattle Cable Railway Company, 1889-1897

Series 44. Stone & Webster Engineering Consulting Corporation, 1910-1912

Series 45. Tacoma Railway and Power Company, 1903-1929

Series 46. Third Street and Suburban Railway Company, 1895-1901

Series 47. Union Trunk Line, 1890-1900

Series 48. Vancouver Traction Company, 1908-1911

Series 49. Washington-Oregon Corporation, 1898-1921

Series 50. Washington Railway and Power Company, 1907

Series 51. West Street and North End Railway Company, 1890-1901

Series 52. Whatcom County Railway & Light Company, 1903-1938 (1903-1915)

Series 53. Whatcom-Fairhaven Gas Company, 1902-1922

Series 54. Other Regional Land, Power and Transportation Companies, 1883-1951