Marshall, also known as Marshall Grist Mill, is a privately owned structure located in Dane County, Wisconsin. It is regulated by the Wisconsin Department of Natural Resources and has state permitting, inspection, and enforcement in place. The primary purpose of Marshall is for recreation, with a gravity dam type and a hydraulic height of 11 feet. Completed in 1870, it stands at a structural height of 15 feet and has a maximum discharge of 1520 cubic feet per second.

With a significant hazard potential and a very high risk assessment rating, Marshall is closely monitored for safety. Its condition assessment is currently rated as fair, with the last inspection conducted in December 2020. The dam has a storage capacity of 1100 acre-feet, with a normal storage of 320 acre-feet and a drainage area of 70.2 square miles. The spillway is of the controlled type with a width of 57 feet, and the structure covers a surface area of 194 acres along Waterloo Creek.

Marshall has a rich history dating back to the 19th century, with modifications made in 1914. It plays a crucial role in water resource management and provides opportunities for recreational activities. Managed by private owners, Marshall serves as a significant landmark in the region and continues to be a focal point for water resource and climate enthusiasts interested in its engineering and environmental impact on the surrounding area.