Lock & Dam #13 is somewhat unusual in that it is located in the middle of the river. There are lengthy earthen dikes on each side of the main control structure. In fact, access, from the Illinois side, is by driving a mile and a half along the earthen embankment.

The main dam structure is 1,066 feet long, and features 10 tainter gates and 3 wider roller gates. The Illinois side consists of a 8,940 foot earth embankment, while the Iowa side has a 4,073 foot earth embankment which includes a 1,650 foot secondary spillway. The locks are typical of the Mississippi River locks being 110 feet wide by 600 feet long. Many of the Mississippi River locks have a second uncompleted auxilliary lock, as does Lock & Dam #13. The auxilliary lock has the upper entrance doors installed and working, but no lower exit doors. The auxilliary lock could be opened if the main lock were to fail.