Lock And Dam No. 20
The structure is located at river mile 343.1. It includes a 2,369 feet (722 m) long dam, 40 tainter gates, 3 roller gates, and a lock chamber that is 110 feet (34 m) wide by 600 feet (183 m) long. There is also an incomplete auxiliary lock. In 2004, the facility was listed in the National Register of Historic Places as Lock and Dam No. 20 Historic District, #04000180 covering 839 acres (340 ha), 1 building, 6 structures, 3 objects.