LaGrande Dam (or La Grande Dam) is a hydroelectric dam on the Nisqually River, on the border of Pierce County and Lewis County, Washington. LaGrande is the lesser of two coordinated dams on the Nisqually, situated two miles north (downstream) of the other, Alder Dam. Both are owned by Tacoma Power.
Hydroelectric power was first produced from LaGrande in November 1912 as the first independent project of Tacoma Power. The present structure was completed in 1945, the same year as Alder Dam's construction. It produces about 65 megawatts, is about 192 feet high, but only holds about 2,700 acre feet (3,300,000 m3) of water.
Neither LaGrande Dam nor its narrow two-mile-long impoundment "LaGrande Reservoir" is accessible to the public.