Lock and Dam No. 9 is located in a bluff-lined valley on the Upper Mississippi River 12 miles upstream from Prairie du Chien, Wis. The project includes a lock, a dam with moveable gates, an earth dike and an overflow spillway. The Corps of Engineers originally placed the facility in operation in July 1937, as part of the Upper Mississippi River 9-foot channel project. After more than 50 years of service, in 1989, the Corps initiated a major maintenance program to replace much of the operating equipment and to construct a new control building to provide reliable service to navigation customers well into the future.

Barge traffic, as well as recreational boats, traversing the Mississippi River glide through Lock and Dam No. 9 at Harpers Ferry. This is an excellent opportunity to introduce young people to the technology of river transportation.

Lock and Dam No. 9 is located south of Lynxville, Wis., and 12 miles north of Prairie du Chien, Wis. It serves as a step in the Upper Mississippi River water stairway of 29 locks and dams. Observation deck is located on the Wisconsin side (Free Admission).