Delton, also known as Mirror Lake, is a gravity dam located in Lake Delton, Wisconsin, with a primary purpose of recreation. Completed in 1931, this structure boasts a height of 19 feet and a hydraulic height of 14 feet, with a storage capacity of 1280 acre-feet. The dam spans 150 feet in length and is situated on Dell Creek, serving as a controlled spillway with a width of 127 feet.

Despite its age, Delton remains in fair condition with a low hazard potential, as indicated by a recent assessment in October 2020. The dam has a very high risk assessment rating of 1, highlighting the importance of ongoing monitoring and maintenance. While it is not under the jurisdiction of the US Army Corps of Engineers, the Wisconsin Department of Natural Resources regulates, inspects, and enforces compliance with state permitting requirements to ensure the safety and integrity of the structure for both recreational and environmental purposes. Overall, Delton stands as a significant water resource in the area, contributing to the local landscape and providing opportunities for outdoor activities.