Founded in 1896, Seattle District provides a full range of civil and military services to the Pacific Northwest.
Seattle District's civil works boundaries encompass 99,000 square miles and contain 4,700 miles of shoreline. The boundaries include the Columbia River system upstream of the mouth of the Yakima River, much of eastern Washington, northern Idaho and western Montana to the Rocky Mountains. The district shares 600 miles of international border with Canada, and the district engineer sits on two International Joint Commission Boards of Control.
Military construction has been a Seattle District mission intermittently since the early 1900s. Work in the early 1900s included constructing defense fortifications in the Puget Sound area and construction of the Lake Washington Ship Canal and the Hiram M. Chittenden Locks. In World War II the district built defense installations in the Northwest and Alaska. The district also assisted in construction of the Alaskan Highway, the Manhattan Project at Hanford, Wash., and missile sites in Montana and Washington.
In 1971 the military mission was transferred to Sacramento District; 10 years later it was returned to Seattle District. Boundaries for Seattle District military work encompass the states of Washington, Oregon, Idaho and Montana.