Lake Koshkonong
A huge, shallow flowage of the Rock River below Fort Atkinson, held back by the Indianford Dam since 1932. Most of the lake is 5 to 7 feet deep with stained water, and it holds good numbers of catfish, walleye, and panfish.
Species
Fishery rating out of 5.
Channel Catfish
The lake's signature bite. Cut bait and nightcrawlers on flats and near the Rock River inlet.
Walleye
Rock River current at the inlet and below Indianford Dam, plus rocky shoreline areas in spring and fall.
White Bass
Schools chase shad in open water. Small spinners and jigs.
Crappie
Shoreline wood and channels in spring.
Northern Pike
Marsh edges and creek mouths early in the year.
When they bite
Month-by-month activity for each target species.
| J | F | M | A | M | J | J | A | S | O | N | D | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Channel Catfish | ||||||||||||
| Walleye | ||||||||||||
| White Bass | ||||||||||||
| Crappie |
Boat launches
5 launch sites. Fees and hours change, so confirm before you go.
- 1Royce-Dallman County ParkPublicRock County park launchDirections ↗
- Newville Public Boat LaunchPublicNear Edgerton, where the Rock River leaves the lakeDirections ↗
- 3Gilbert Bay (Vinnie Ha Ha Rd)PublicPublic access on the east sideDirections ↗
- 4Kuehn RoadPublicPublic access on the north shoreDirections ↗
- Charley Bluff Road AccessPublicWDNR-listed public accessDirections ↗
Size & creel limits
Special rules for this lake, confirmed from official state regulations. Minimum size and daily limit.
| Species | Min size | Daily limit |
|---|---|---|
| Walleye Open all year (includes sauger/hybrids) | 18 in | 3 / day |
| Largemouth/Smallmouth Bass Open all year | 14 in | 5 / day |
| Northern Pike Open all year | 26 in | 2 / day |
| Muskellunge May 2-Dec 31, 2026; open water only | 40 in | 1 / day |
| Panfish Open all year | See Wisconsin rules book ↗ | 25 / day |
| Catfish Open all year | See Wisconsin rules book ↗ | 10 / day |
| Lake Sturgeon No fishing allowed | Closed | 0 |
Other species in this lake: look up the limits at Wisconsin DNR ↗
Bait & tackle nearby
Closest shops to the lake and its boat launches. Call ahead for live bait and hours.
- Bait Box on the RockNearby1240 Riverside Drive, Fort Atkinson(920) 691-2602Directions ↗
- Dunham's Sports8.6 mi1800 Humes Road, Janesville · closest to Royce-Dallman County Park(608) 755-4935Directions ↗
- It's A Keeper Bait & Tackle12.3 mi815 South Washington Street, Janesville · closest to Royce-Dallman County Park(608) 757-2061Directions ↗
Local tips
- With a 7 ft maximum depth, wind churns the whole lake. Pick calm days and watch for sudden waves.
- Shallow water warms fast, so the spring bite starts early.
- Algae blooms happen in summer. Check water advisories before swimming.
Angler reports
Water temp, what's biting, and anything else other anglers should know about Lake Koshkonong.
View on interactive map
Zoom and pan on a street, satellite or terrain map. Red pins are boat launches; blue pins are bait shops nearby.