The lake bed in 3-D: deep basin, drop-offs and shoreline. Shape estimated, not for navigation. Spot 1 (upper arm) is open for everyone; the other 3 come with LakeScope PRO. Full screen
Lake Koshkonong
Jefferson County, Wisconsin · 10,500 acres (16.3 sq mi)
49°F water, level steady, windy Friday (15 mph N).
About Lake Koshkonong
Lake Koshkonong spreads over 10,500 acres in Jefferson County, Wisconsin. Lake Koshkonong, one of Wisconsin's largest inland lakes, averages only about 6 feet deep.
It stretches about 5.8 miles end to end with roughly 24 miles of shoreline. At about 780 ft above sea level, it follows the seasons of the region. It reaches about 7 ft at its deepest, with an average depth near 6 ft. Lake Koshkonong sits right on the water. The closest city is Janesville, about 10 miles away.
- Size
- 10,500 acres (16.3 sq mi)
- Deepest
- About 7 ft (average 6 ft)
- Shoreline
- About 24 miles
- End to end
- About 5.8 miles
- Elevation
- About 780 ft
- Type
- Natural lake raised by a dam
- Dam
- Indianford Dam
- County
- Jefferson County
The lake from above
Best fishing times
Saturday Good
- 6:15 am – 8:30 amsunrise · wind 5 mph
- 3:00 pm – 5:15 pm bestsunset, moon overhead · wind 5 mph
Sunday Good
- 6:15 am – 8:30 amsunrise · wind 0 mph
- 3:45 pm – 5:15 pm bestsunset, moon overhead · wind 5 mph
Based on sun and moon times and the wind forecast. A guide, not a promise. The app shows the whole week.
Fish in Lake Koshkonong
Anglers come to Lake Koshkonong for muskie, largemouth bass, smallmouth bass, northern pike, walleye and catfish. At 49°F on the surface right now, here is how each one should behave.
- GoodMuskie
Fall feed. Big baits along weed edges and breaks.
- FairLargemouth bass
Cooling down. Try slow baits on points and deeper channel edges.
- FairSmallmouth bass
Picking up. Look on rocky points and gravel.
- GoodNorthern pike
Prime range. Weed edges and shallow bays.
- GoodWalleye
Good cool-water bite, best at dusk and after dark.
From today's water temperature and the season. A guide, not a promise.
Fishing spots
- 1Upper arm
The lake narrows toward the incoming river or creek; moving water carries food.
- 2
- 3
- 4
3 more spots with LakeScope PRO: fish, depth band, water temperature, best time and bait for each.
Picked from the shape of the lake bed. A guide, not a promise.
Water temperature
At the surface, seen .
Water level
Steady over 7 days.
Latest reading .
Ice
Open water
Ice thickness is an estimate from air temperature, not a measurement. Check the ice yourself before going on it.
Weather and wind
Sunrise 6:45 am · sunset 4:34 pm · waxing crescent moon (lake time).
Towns and places to stay near Lake Koshkonong
- Lake Koshkonongon the shore
- Edgertonabout 2.9 mi southwest
- Fort Atkinsonabout 4.2 mi northeast
- Miltonabout 4.6 mi south
- Janesvillenearest city, about 10 mi south
Prices and availability come from booking partners; we may earn a commission at no cost to you.
Questions about Lake Koshkonong
What fish are in Lake Koshkonong?
Lake Koshkonong holds muskie, largemouth bass, smallmouth bass, northern pike, walleye and catfish. Check the state fish and wildlife agency for stocking and limits.
How deep is Lake Koshkonong?
About 7 ft at the deepest point, about 6 ft on average. The 3-D view shows where the deep water is.
How big is Lake Koshkonong?
10,500 acres, with about 24 miles of shoreline.
What town is near Lake Koshkonong?
Lake Koshkonong is on the shore; Edgerton is about 2.9 miles southwest.
What is the water temperature at Lake Koshkonong today?
The surface was about 49°F on the latest clear reading. The page updates every day.
Lake Koshkonong on your phone
The whole week of bite times, lake alerts and the 3-D view, every morning.
