Petenwell Lake is Wisconsin's second largest inland lake at 23,040 acres, created in 1948 by damming the Wisconsin River. The lake is 14 miles long and 2 miles wide, with a maximum depth of 42 feet. Paddlers should be aware that Petenwell's large size can create challenging conditions, with potentially rough waves and strong winds, especially in the afternoon. Mornings typically offer calmer waters. The lake's expansive open water areas require careful planning and awareness of weather conditions.

Several public boat launches provide access, including the 3rd Street launch on the northwest side. The lake features diverse paddling environments, from protected sloughs and backwaters to wide open stretches. An archipelago of islands in the northeast offers interesting exploration opportunities. The northwest shore is notable for impressive sandbanks, with Yellow Banks and a large sandbank near 25th Avenue being highlights.

Wildlife sightings may include bald eagles, great blue herons, and various fish species. The lake supports walleye, northern pike, bass, and panfish. Water quality can be affected by algae blooms in summer. Petenwell's shoreline is largely undeveloped, providing a natural setting, though some areas have homes and piers.

For a scenic day trip, paddlers might consider a 9-mile one-way route from Plank Hill Small Boat Access to Longview Point Access, passing seven sandbanks. The lake offers opportunities for fishing, swimming, and camping at several parks along the shore. Paddlers should be mindful of motorboat traffic, especially on weekends and holidays.