Deepest Depth: 87 feet
Latitude: 43.083333
Longitude: -88.9333
Counties: Jefferson
Cities: Jefferson

Information: Rock Lake is in south central Wisconsin, at Lake Mills, Wisconsin in Jefferson County, Wisconsin approximately 20 miles (32 km) east of Madison. It is 87 feet (27 m) at its deepest point. Lake Mills is a quaint small town. Mounds shaped like pyramids exist three miles (5 km) east of Rock Lake in a State Park called Aztalan State Park, on the Crawfish River in the town of Aztalan, Wisconsin. The park has National Landmark Status and is a Midwestern archeological treasure. The mounds are thought to have been built by the Mississippian Mound Builders, and it is speculated that the site at Aztalan is a northern outpost of Cahokia, a much larger city in present day Illinois not far from St. Louis, Missouri. The waters of Rock Lake have also been referred to as "Tyranena", (Tie-ra-nee-na) and that name has persisted in the area as well, and is used by businesses, road names and a park that is on the lake. Rock Lake is perhaps most famous for its underwater "pyramids" believed by some to be built by the Aztalan natives at a time when water levels were much lower.