Lock and Dam No. 20 is a lock and dam located on the Upper Mississippi River, the lock side in Canton, Missouri and the dam crossing to Meyer, Illinois. The structure is located at river mile 343.1. It includes a 2369 ft long dam, 40 tainter gates, 3 roller gates, and a lock chamber that is 110 ft wide by 600 ft 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 acre, 1 building, 6 structures, 3 objects.

History

The Lock and Dam are on the site of the former town of Tully, Missouri. Tully was founded in 1834 and became a thriving river port and regional business hub until being virtually destroyed by major flooding in 1851. Left a crumbling "ghost town", what little that remained of Tully was finally removed during Lock and Dam No. 20's construction.