Though relatively large in acreage, Lake Koshkonong is unusually shallow compared to other lakes of its size. Much of the lake is less than five feet deep!
Walleye are the species of choice here, and highly pursued by many anglers. However, Lake Koshkonong does hold a variety of other fish species including muskie, northern pike, bass, catfish, panfish and carp.
Be warned that the lake can become extremely rough in a short period of time due to it being a large and shallow body of water. Winds of 15 miles per hour or more can create dangerous conditions. A number of beacons have been placed around the lake to aid in navigation.
Underground springs, pressure cracks and the influence of the Rock River affect the formation of safe ice on the lake, so it is important to use caution during the winter months as well.
The Rock River and Lake Koshkonong receive heavy boating pressure. Certain areas have been posted with “no wake” buoys. The Rock River inlet and upstream through Fort Atkinson has been marked with buoys to mark the safe navigation channel.
Due to the influence of carp and turbid water conditions, aquatic vegetation is limited to shallow bays. The lake association has attempted to introduce pondweed and wild celery to improve fish and waterfowl habitat.
Interactive Lake Map
For a more detailed lake map and up to the minute fishing reports, follow the Lake Koshkonong waterway page on Fishidy.
Here are some tips for locating and catching fish on Lake Koshkonong:
- Early season walleye fishing is focused on the Rock River from its mouth on the northeast end of the lake upstream to the rapids located above Fort Atkinson. Walleye will stage at the mouth area until water temperatures reach approximately 43 degrees. Fast current and cool water temperatures require a slow and accurate presentation here. Jigs in chartreuse or green, tipped with a 2- to 3-inch fathead minnow, will produce good results.
- Schools of white bass roam the lake and are caught by anglers trolling for walleye. White bass typically will hit baits that are trolled faster than for walleye. When making turns, outside lines of walleye anglers tend to catch white bass. Anglers specifically fishing for white bass will troll using Shad Raps in blue colors and Heddon red/white Sonics.
- Springs found on the east end of the lake are great places to find northern pike from summer through fall. The fish are attracted to cooler water temperatures. Spoons, in-line spinners and bass-style spinnerbaits are the most common lures used.
- Woody cover such as brush, overhanging willows and deadfalls are great places to look for crappie during spring. After their spawn, crappie can be found near the springs and in deeper water of bays.
- The Rock River below the lake and the southwest corner of the lake will hold the largest number of bluegill from spring through fall. Fish will seek out docks and overhanging brush for cover. Slip-knot bobber rigs tipped with worms are the most productive method for catching bluegill.