7 is a lock and dam located on the Upper Mississippi River at river mile 702.5 near the cities of La Crescent, Minnesota and Onalaska, Wisconsin.

The facility was constructed in the mid-1930s and placed in operation in April 1937.

The lock and dam are owned and operated by the St. Paul District of the United States Army Corps of Engineers-Mississippi Valley Division.

The lock and dam system consists of a concrete structure 940 feet (286.5 m) long with five roller gates and 11 tainter gates, a segment of earth embankment 8,100 feet (2,468.9 m) long from the dam to French Island separated by a concrete spillway 1,000 feet (304.8 m) long, and another embankment 2,400 feet (731.5 m) long from French Island to Onalaska which has a concrete spillway 670 feet (204.2 m) long.

[3] The lock and dam is one of the most visited because of its proximity to Interstate 90, and is clearly visible to travelers crossing the I-90 Mississippi River Bridge.