History of Bonneville Dam

100 Bonneville Lock and Dam consists of a number of dam structures that together complete a span of the Columbia River between the US states of Oregon and Washington at River Mile 146.1. The dam is situated 40 miles east of Portland, Oregon, in what is now the Columbia River Gorge National Scenic Area. The key functions of Bonneville Lock and Dam are those of electrical power creation and river navigation. The dam was built and is managed by the US Army Corps of Engineers. Electrical power generated at Bonneville is dispersed by the Bonneville Power Administration. Bonneville Lock and Dam are named for Army Capt. Benjamin Bonneville, an early explorer credited with charting much of the Oregon Trail. The name is pronounced BAH-nee-vill.


The original structures: a lock and powerhouse constructed on the south side of Bradford Island and a spillway on the north side were built by the Army Corps of Engineers during the New Deal—started in 1933 and finished in 1937. Prior to this damming of the river, a set of curls that were opened in 1896 moved ships around Cascades Rapids, situated several miles upstream of Bonneville. Both the cascades and the old lock structure were submerged by Lake Bonneville, the reservoir that formed behind the dam. The original navigation lock at Bonneville was opened in 1938 and was, at that time, the largest single-lift lock in the world.