Lock and Dam No. 24 is a lock and dam located near Clarksville, Missouri around river mile 273.4 on the Upper Mississippi River. The main lock is 110 ft wide and 600 ft long with its bottom at an elevation of 430 feet. The auxiliary lock is not operational. Normal pool elevation behind the dam is 449 feet. The movable portion of the dam is 1340 ft long and consists of 15 submersible, elliptical, tainter gates. A 2720 ft submersible earthen dike extends from the movable dam to the Illinois shore. In 2004, the facility was listed in the National Register of Historic Places as Lock and Dam No. 24 Historic District, #04000183 covering 1027 acre, 3 buildings, 15 structures, 4 objects.