From Washington to you
McNary Dam
McNary Dam · Benton County · construction began 1947
The Corps places this Columbia River dam at Umatilla, Washington, river mile 292, with a 64-mile reservoir that reaches Hanford.
McNary Lock and Dam was authorized in the 1945 Rivers and Harbors Act and named for Senator Charles L. McNary. Construction began in 1947. All turbine units were operating in 1957. The Corps lists the location as Umatilla, Washington, at Columbia River mile 292. The project spans the river between Oregon and Washington.
The dam is 7,365 feet long and about 183 feet above the streambed. Lake Wallula extends 64 miles upstream to Hanford and has over 242 miles of shoreline. Fourteen units produce 980 megawatts, enough for about 686,000 homes.
The source below is the Corps Northwestern Division fact sheet.
- Geography & Geology
- History
Sources (1)
government · Tier S
U.S. Army Corps of EngineersMcNary Dam and Lake Wallula
Last reviewed: September 20, 2026
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