Located in the Columbia Gorge National Scenic Area 40 miles east of Portland, Oregon, and Vancouver, Washington, Bonneville Lock and Dam spans the Columbia and links the two states. The U.S. Army Corps of Engineers operates and maintains Bonneville Lock and Dam for hydropower production, fish and wildlife protection, recreation and navigation. Since 1938, Bonneville Dam has supplied the region with inexpensive electrical power. Visitors can experience first-hand the operation of two hydroelectric powerhouses and watch migrating fish traveling upstream at the underwater viewing rooms next to the fish ladders.