Horicon, also known as Lower Horicon, is a state-owned dam located in Dodge County, Wisconsin. Built in 1930, this Gravity-type dam spans 200 feet in length and stands at a height of 12 feet, with a storage capacity of 20,000 acre-feet. The dam serves a primary purpose of "Other" and is regulated by the Wisconsin Department of Natural Resources (WIDNR), with inspection, permitting, and enforcement all being carried out by the state agency.

With a drainage area of 455 square miles and a maximum discharge of 12,500 cubic feet per second, Horicon plays a crucial role in managing water levels in the Main Ditch river or stream. Despite its age, the dam has been assessed as being in satisfactory condition and poses a low hazard potential. However, its risk assessment is rated as very high, indicating the importance of ongoing monitoring and management to ensure the safety and effectiveness of the structure for both water resource management and climate resilience in the region.