What is the deepest lake in Wisconsin?

Of the lakes with a published depth, Green Lake is the deepest at about 237 ft.

Deepest lakes in Wisconsin: 10 lakes ranked by depth

The deepest lakes in Wisconsin with a published depth, deepest first. Deep lakes stay cold below the surface all summer, which is what trout and big predators want.

Deepest first

#	Lake	Deepest	Size
1	Green Lake	about 237 ft	7,350 acres
2	Geneva Lake	about 135 ft	5,400 acres
3	Trout Lake	about 117 ft	3,970 acres
4	Chippewa Flowage	about 92 ft	14,600 acres
5	Lake Mendota	about 83 ft	9,740 acres
6	Lake Monona	about 74 ft	3,270 acres
7	Grindstone Lake	about 60 ft	3,180 acres
8	Minocqua Lake	about 60 ft	1,360 acres
9	Turtle Flambeau Flowage	about 49 ft	12,900 acres
10	Pewaukee Lake	about 46 ft	2,440 acres

1. Green Lake

At 7,350 acres, Green Lake is a good-sized lake. The lake is about 22 miles northeast of Oshkosh. It holds largemouth bass, smallmouth bass, walleye and northern pike. It goes down to about 237 ft. At 237 feet deep, Green Lake is the deepest natural inland lake in Wisconsin.

Green Lake today: water temperature, bite times and the 3-D lake bed

2. Geneva Lake

Geneva Lake covers some 5,400 acres. The fish here are smallmouth bass, largemouth bass, northern pike and yellow perch. At about 135 ft deep, it stays cooler below the surface well into summer. Its bed shows three point drop-offs and an upper arm worth a first look.

Geneva Lake today: water temperature, bite times and the 3-D lake bed

3. Trout Lake

Trout Lake spreads over some 3,970 acres. It lies about 9.8 miles southwest of Lac du Flambeau. Expect lake trout, walleye, northern pike and muskie. It goes down to about 117 ft. On the 3-D map the bed has three point drop-offs and a sheltered cove: good places to start. Trout Lake is one of the primary research lakes of the North Temperate Lakes Long-Term Ecological Research site, one of the longest-running lake studies in the world. It is a clear lake, so long casts and a quiet approach pay off.

Trout Lake today: water temperature, bite times and the 3-D lake bed

4. Chippewa Flowage

Chippewa Flowage covers 14,600 acres. It lies about 69 miles northwest of Duluth. Winter Dam holds it on the Chippewa River. It holds muskie. It goes down to about 92 ft. The lake bed gives you three point drop-offs and two sheltered coves to work. The Chippewa Flowage is Wisconsin's third-largest lake, created in 1923 by the Winter Dam on the Chippewa River.

Chippewa Flowage today: water temperature, bite times and the 3-D lake bed

5. Lake Mendota

At some 9,740 acres, Lake Mendota is a good-sized lake. You will find it right by Maple Bluff. Expect northern pike, white bass, walleye and largemouth bass. At about 83 ft deep, it stays cooler below the surface well into summer. Its bed shows three point drop-offs and an upper arm worth a first look. Lake Mendota is the largest of Madison's four connected Yahara lakes and one of the most-studied lakes in the world.

Lake Mendota today: water temperature, bite times and the 3-D lake bed

6. Lake Monona

Lake Monona covers some 3,270 acres. The lake is right by Monona. It holds bluegill, largemouth bass, smallmouth bass and muskie. It goes down to about 74 ft. On the 3-D map the bed has three point drop-offs and an upper arm: good places to start. Lake Monona is one of Madison's four connected Yahara lakes.

Lake Monona today: water temperature, bite times and the 3-D lake bed

7. Grindstone Lake

Grindstone Lake is a natural lake of some 3,180 acres. The lake is near Little Round Lake. Like most lakes its size in Wisconsin, it should hold walleye, northern pike, largemouth bass and smallmouth bass. At about 60 ft deep, it stays cooler below the surface well into summer. Grindstone Lake lies along a historic portage route linking the Chippewa River and St. Croix River watersheds.

Grindstone Lake today: water temperature, bite times and the 3-D lake bed

8. Minocqua Lake

Minocqua Lake spreads over 1,360 acres of water. The lake is about 11 miles northwest of Lac du Flambeau. Expect muskie, largemouth bass, smallmouth bass and northern pike. The deepest water is around 60 ft. Lake Minocqua surrounds the town of Minocqua, with a bridge crossing the lake near its southwestern shore.

Minocqua Lake today: water temperature, bite times and the 3-D lake bed

9. Turtle Flambeau Flowage

At 12,900 acres, Turtle Flambeau Flowage is a big lake. The lake is near Lac du Flambeau. It is the Flambeau River behind Turtle Dam. Muskie, largemouth bass, smallmouth bass and northern pike are the draw. The deepest water is around 49 ft. Its bed shows three point drop-offs and two sheltered coves worth a first look.

Turtle Flambeau Flowage today: water temperature, bite times and the 3-D lake bed

10. Pewaukee Lake

Pewaukee Lake is a natural lake of 2,440 acres of water. The lake is about 5 miles southeast of Waukesha. Expect bluegill, largemouth bass, smallmouth bass and muskie. It goes down to about 46 ft. Its bed shows three point drop-offs and an upper arm worth a first look. Pewaukee Lake is the largest lake in Waukesha County's 'Lake Country' and hosts national sailing events.

Pewaukee Lake today: water temperature, bite times and the 3-D lake bed

The clearest of them

Trout Lake is known for clear water. On a clear lake fish see a long way: lighter line, natural colours and longer casts make the difference.

Fishing deep water

In summer a deep lake splits into a warm top layer and a cold bottom; fish hold near the line between them, often 20 to 40 ft down. A depth finder, a slow troll or a jig dropped straight down finds them.