Hudson Bay, also known as Moquah Lake, is a gravity dam located in Ashland, Wisconsin, along the Brunsweiler River. Constructed in 1969, this dam serves primarily for recreation purposes, with a maximum storage capacity of 672 acre-feet and a normal storage of 560 acre-feet. The dam has a structural height of 7.7 feet and a hydraulic height of 5 feet, with a length of 56 feet and a surface area of 240 acres.

Managed by the Wisconsin Department of Natural Resources (WIDNR), Hudson Bay is regulated, inspected, and enforced by the state agency to ensure safety and compliance with regulatory standards. Despite being classified as having a low hazard potential, the dam's risk assessment is rated as very high, indicating the importance of risk management measures. The last inspection of the dam was conducted in May 2011, with an inspection frequency of 10 years.

Overall, Hudson Bay offers a picturesque recreational setting for water resource and climate enthusiasts to enjoy and appreciate the beauty of Wisconsin's natural landscapes. With its tranquil waters and surrounding natural environment, the dam provides an opportunity for outdoor activities and wildlife observation, making it a valuable resource for both locals and visitors alike. As efforts continue to monitor and maintain the dam's safety, Hudson Bay remains a vital asset for the community's recreational and environmental well-being.