Petenwell Lake
Lake Petenwell is a man-made lake in central Wisconsin, in Adams, Juneau, and Wood counties next to Castle Rock Lake. It covers over and is deep. Lake Petenwell is Wisconsin's second largest lake at or approximately . It was created in 1948 by the Wisconsin River Power Company with the construction of a dam across the Wisconsin River near Necedah. It has a maximum depth of and is used for skiing, sailing and fishing. Private lakefront property is very limited as most of the virgin shoreline is undeveloped forest. Wildlife includes wintering bald eagles. Game fish include  walleye, northern pike, bass, panfish, and muskellunge. The area around the lake has restaurants, a community theater, a golf course and two casinos. Algae. Blue-green algae was reported in the lake in 2013. In 2019, Adams County website stated that the beaches were not closed due to algae, and that the situation was being monitored.