The Corps’ navigation responsibilities are planning and constructing navigation channels, locks and dams, and dredging to maintain channel depths in U.S. harbors and inland waterways. We operate and maintain 25,000 miles of navigable channels and 196 commercial lock and dam sites and are responsible for harbors and waterways in 41 states. In partnership with local port authorities, Corps personnel oversee dredging and construction projects at hundreds of ports and harbors. Ten of the Corps’ 237 locks are located in Northwestern Division — eight on the Columbia/Snake rivers, one on the Willamette River, and one at Lake Washington in Seattle. The Division also maintains 22 deep draft harbors, 20 shallow draft harbors and more than 1,700 miles of navigable waterways in the Columbia and Missouri basins.