Name Location Coordinates River Capacity (MW ) Operator Year opened Alder Dam Pierce County, Washington 46°48′06″N 122°18′37″W / 46.801600°N 122.310200°W / 46.801600; -122.310200 (Alder Dam ) Nisqually River 50 Tacoma Power 1945 [6] Bonneville Dam Skamania County, Washington Multnomah County, Oregon 45°38′39″N 121°56′28″W / 45.6441°N 121.9410°W / 45.6441; -121.9410 (Bonneville Dam ) Columbia River 1,093 United States Army Corps of Engineers 1938, 1981 [4] electricity generated in Oregon Boundary Dam Metaline Falls, Washington 48°59′14″N 117°20′52″W / 48.9871°N 117.3478°W / 48.9871; -117.3478 (Boundary Dam ) Pend Oreille River 1,024 Seattle City Light 1967 [4] Box Canyon Dam Ione, Washington 48°46′51″N 117°25′06″W / 48.7809°N 117.4183°W / 48.7809; -117.4183 (Box Canyon Dam ) Pend Oreille River 90 Pend Oreille PUD 1955 [4] Cedar Falls Dam Cedar Falls, Washington 47°25′09″N 121°46′55″W / 47.4193°N 121.7819°W / 47.4193; -121.7819 (Cedar Falls Dam ) Cedar River (Washington) 30 Seattle City Light 1921, 1929 [4] Chief Joseph Dam Douglas County, Washington Okanogan County, Washington 47°59′42″N 119°38′25″W / 47.9951°N 119.6404°W / 47.9951; -119.6404 (Chief Joseph Dam ) Columbia River 2,620 United States Army Corps of Engineers 1958, 1973 [4] Cowlitz Falls Dam Lewis County, Washington 46°27′58″N 122°06′35″W / 46.4661°N 122.1097°W / 46.4661; -122.1097 (Cowlitz Falls Dam ) Cowlitz River 70 Lewis County Public Utilities District 1994 [7] Cushman Dam No. 1 Mason County, Washington 47°25′05″N 123°13′31″W / 47.4181°N 123.2252°W / 47.4181; -123.2252 (Cushman Dam 1 ) Skokomish River 43 Tacoma Power 1926 [8] Cushman Dam No. 2 Mason County, Washington 47°22′11″N 123°09′37″W / 47.3698°N 123.1603°W / 47.3698; -123.1603 (Cushman Dam 2 ) Skokomish River 81 Tacoma Power 1930–1931, 1952, 2013 [8] Diablo Dam Whatcom County, Washington 48°42′50″N 121°07′54″W / 48.7139°N 121.1317°W / 48.7139; -121.1317 (Diablo Dam ) Skagit River 159 Seattle City Light 1936–1937 [4] Electron Hydroelectric Project Pierce County, Washington 46°59′28″N 122°10′30″W / 46.9910°N 122.1749°W / 46.9910; -122.1749 (Electron Hydroelectric Project ) Puyallup River 26 Electron Hydro, LLC. 1904, 1929 [4] Gorge Dam Whatcom County, Washington 48°41′53″N 121°12′31″W / 48.6981°N 121.2086°W / 48.6981; -121.2086 (Gorge Dam ) Skagit River 199 Seattle City Light 1924, 1929, 1951 [4] Grand Coulee Dam Grant and Okanogan counties 47°57′27″N 118°58′38″W / 47.9575°N 118.9773°W / 47.9575; -118.9773 (Grand Coulee Dam ) Columbia River 6,809 United States Bureau of Reclamation 1941, 1975 [4] Includes 314 MW pumped-storage Henry M. Jackson Dam Snohomish County, Washington 47°54′30″N 121°48′52″W / 47.9084°N 121.8144°W / 47.9084; -121.8144 (H M Jackson Dam ) Sultan River 112 Snohomish County Public Utility District 1984 [9] Ice Harbor Dam Franklin and Walla Walla counties 46°14′59″N 118°52′47″W / 46.2498°N 118.8798°W / 46.2498; -118.8798 (Ice Harbor Dam ) Snake River 603 United States Army Corps of Engineers 1962, 1975–1976 [4] Lake Chelan Dam Chelan, Washington 47°50′05″N 120°00′48″W / 47.8347°N 120.0133°W / 47.8347; -120.0133 (Lake Chelan Dam ) Chelan River 62.1 Chelan County Public Utility District 1927–1928 [10] LaGrande Dam Pierce County, Washington 46°49′58″N 122°19′11″W / 46.8328°N 122.3196°W / 46.8328; -122.3196 (LaGrande Dam ) Nisqually River 64 Tacoma Power 1912, 1945 [11] Little Goose Dam Columbia and Whitman counties 46°35′02″N 118°01′38″W / 46.5838°N 118.0273°W / 46.5838; -118.0273 (Little Goose Dam ) Snake River 932 United States Army Corps of Engineers 1970–1971, 1978 [4] Long Lake Dam Lincoln County, Washington 47°50′04″N 117°50′10″W / 47.8344°N 117.8361°W / 47.8344; -117.8361 (Long Lake Dam ) Spokane River 71 Avista Utilities 1915, 1919, 1924 [12] Lower Baker Dam Skagit County, Washington 48°32′52″N 121°44′27″W / 48.5478°N 121.7407°W / 48.5478; -121.7407 (Lower Baker Dam ) Baker River (Washington) 79 Puget Sound Energy 1960, 2013 [4] Lower Granite Dam Garfield and Whitman counties 46°39′34″N 117°25′46″W / 46.6595°N 117.4294°W / 46.6595; -117.4294 (Lower Granite Dam ) Snake River 932 United States Army Corps of Engineers 1975, 1978 [4] Lower Monumental Dam Franklin and Walla Walla counties 46°33′49″N 118°32′23″W / 46.5635°N 118.5397°W / 46.5635; -118.5397 (Lower Monumental Dam ) Snake River 932 United States Army Corps of Engineers 1969–1970, 1979 [4] Mayfield Dam Lewis County, Washington 46°30′13″N 122°35′19″W / 46.5035°N 122.5885°W / 46.5035; -122.5885 (Mayfield Dam ) Cowlitz River 162 Tacoma Power 1963, 1983 [13] Merwin Dam Clark and Cowlitz counties 45°57′24″N 122°33′16″W / 45.956700°N 122.554444°W / 45.956700; -122.554444 (Merwin Dam ) Lewis River (Washington) 136 PacifiCorp 1931–1932, 1949, 1958 [4] Mossyrock Dam Lewis County, Washington 46°32′05″N 122°25′29″W / 46.5347°N 122.4247°W / 46.5347; -122.4247 (Mayfield Dam ) Cowlitz River 300 Tacoma Power 1968 [14] Priest Rapids Dam Grant and Yakima counties 46°38′42″N 119°54′29″W / 46.6451°N 119.9080°W / 46.6451; -119.9080 (Priest Rapids ) Columbia River 955 Grant County Public Utility District 1959–1961 [4] Rock Island Dam Chelan and Douglas counties 47°20′46″N 120°05′30″W / 47.3461°N 120.0917°W / 47.3461; -120.0917 (Rock Island Dam ) Columbia River 660 Chelan County Public Utility District 1931–1932, 1952–1953, 1978–1979 [4] Rocky Reach Dam Chelan and Douglas counties 47°32′01″N 120°17′43″W / 47.5336°N 120.2953°W / 47.5336; -120.2953 (Rocky Reach Dam ) Columbia River 1,300 Chelan County Public Utility District 1961, 1973–1974 [4] Ross Dam Whatcom County, Washington 48°43′57″N 121°04′04″W / 48.7326°N 121.0679°W / 48.7326; -121.0679 (Ross Dam ) Skagit River 353 Seattle City Light 1952–1956 [4] Snoqualmie Falls Hydroelectric Plant Snoqualmie, Washington 47°32′24″N 121°50′13″W / 47.5401°N 121.8370°W / 47.5401; -121.8370 (Snoqualmie Falls Hydroelectric Plant ) Snoqualmie River 54 Puget Sound Energy 1898, 1957, 2013 [4] Swift Dam Skamania County, Washington 46°03′39″N 122°12′06″W / 46.0608°N 122.2017°W / 46.0608; -122.2017 (Swift Dam 1 ) 46°03′34″N 122°15′34″W / 46.059400°N 122.259400°W / 46.059400; -122.259400 (Swift Dam 2 ) Lewis River (Washington) 240 PacifiCorp 1958–1959 [4] Upper Baker Dam Whatcom County, Washington 48°38′56″N 121°41′27″W / 48.6490°N 121.6907°W / 48.6490; -121.6907 (Upper Baker Dam ) Baker River (Washington) 91 Puget Sound Energy 1959 [4] Wanapum Dam Grant and Kittitas counties 46°52′23″N 119°58′13″W / 46.8731°N 119.9703°W / 46.8731; -119.9703 (Wanapum Dam ) Columbia River 1,038 Grant County Public Utility District 2011-2018 [4] Wells Dam Chelan and Douglas counties 47°56′49″N 119°51′55″W / 47.9469°N 119.8653°W / 47.9469; -119.8653 (Wells Dam ) Columbia River 851 Douglas County Public Utility District 1967–1969 [4] Wynoochee Dam Grays Harbor County, Washington 47°23′06″N 123°36′19″W / 47.3851°N 123.6052°W / 47.3851; -123.6052 (Wynoochee Dam ) Wynoochee River 12.8 Tacoma Power 1994 [4] Yale Dam Clark and Cowlitz counties 45°57′46″N 122°20′08″W / 45.9628°N 122.3355°W / 45.9628; -122.3355 (Yale Dam ) Lewis River (Washington) 134 PacifiCorp 1953 [4]