WI · ranked by public data

The 23 Deepest Lakes in Florence County, Wisconsin

23 Florence County lakes are at least 50 acres with a documented maximum depth, out of 108 documented lakes in the county. Updated July 2026.

182 ft
114 acres
Florence County, WI
Sea Lion Lake
enhancedDepth mapWater data
45.88, -88.32114 acres | 82 ft max1 public access pointPanfish, Largemouth Bass
82 ft maximum depth · 114 acres · 1 public landing
275 ft
73 acres
Florence County, WI
Long Lake
enhancedDepth mapWater data
45.89, -88.1373 acres | 75 ft max0 public access pointsPanfish, Largemouth Bass
75 ft maximum depth · 73 acres · No verified public access
374 ft
195 acres
Florence County, WI
Keyes Lake
enhancedDepth mapAIS recordedWater data
45.90, -88.31195 acres | 74 ft max1 public access pointLargemouth Bass, Panfish
74 ft maximum depth · 195 acres · 1 public landing
468 ft
104 acres
Florence County, WI
Bass Lake
enhancedDepth mapWater data
45.89, -88.14104 acres | 68 ft max0 public access pointsPanfish, Largemouth Bass
68 ft maximum depth · 104 acres · No verified public access
564 ft
297 acres
Florence County, WI
Brule River Flowage
enhancedDepth map
45.95, -88.22297 acres | 64 ft max0 public access pointsSmallmouth Bass, Walleye
64 ft maximum depth · 297 acres · No verified public access
654 ft
83 acres
Florence County, WI
Middle Lake
enhancedDepth mapWater data
45.90, -88.1483 acres | 54 ft max0 public access pointsPanfish, Largemouth Bass
54 ft maximum depth · 83 acres · No verified public access
752 ft
254 acres
Florence County, WI
Patten Lake
enhancedDepth mapWater data
45.85, -88.42254 acres | 52 ft max1 public access pointPanfish, Largemouth Bass
52 ft maximum depth · 254 acres · 1 public landing
845 ft
84 acres
Florence County, WI
Lost Lake
enhancedDepth mapWater data
45.88, -88.5684 acres | 45 ft max1 public access pointSmallmouth Bass, Trout
45 ft maximum depth · 84 acres · 1 public landing
944 ft
50 acres
Florence County, WI
Seidel Lake
enhancedDepth mapWater data
45.87, -88.3550 acres | 44 ft max1 public access pointLargemouth Bass, Panfish
44 ft maximum depth · 50 acres · 1 public landing
1043 ft
183 acres
Florence County, WI
Emily Lake
enhancedDepth mapWater data
45.87, -88.28183 acres | 43 ft max1 public access pointLargemouth Bass, Walleye
43 ft maximum depth · 183 acres · 1 public landing

Rank	Lake	County	Max depth	Acres	Public access
11	North Lake	Florence	43 ft	79	1 landing
12	Bass Lake	Florence	42 ft	51	1 landing
13	Fisher Lake	Florence	42 ft	50	2 landings
14	Pine River Flowage	Florence	35 ft	123	2 landings
15	Cosgrove Lake	Florence	26 ft	76	—
16	Ellwood Lake	Florence	25 ft	130	1 landing
17	West Lake	Florence	25 ft	72	—
18	Long Lake	Florence	21 ft	353	1 landing
19	West Bass Lake	Florence	19 ft	55	1 landing
20	Lake of Dreams	Florence	15 ft	62	1 landing
21	Halsey Lake	Florence	10 ft	506	1 landing
22	Fay Lake	Florence	10 ft	272	1 landing
23	Reisner Lake	Florence	5 ft	96	—

Methodology

How this list is built

Ranked strictly by documented maximum depth from DNR lake records. No estimates, no hearsay depths.
Lakes without a documented maximum depth are excluded rather than guessed at.
Lakes under 50 acres — or without documented acreage — are excluded from rankings.
Public access is shown for every lake but never affects the ranking — a deep lake ranks whether or not you can launch on it.

FAQ

Florence County lake records

What is the deepest lake in Florence County?

Sea Lion Lake — Sea Lion Lake in Florence County is the deepest documented lake in Florence County, at 82 feet maximum depth.

Deepest lakes statewide Biggest lakes in Florence County Clearest lakes in Florence County Lakes with the most public access in Florence County All Florence County lakes

Source data: Wisconsin DNR lake and monitoring records as aggregated by LakeList. Figures reflect the most recent documented values, not new surveys — verify access and rules before you go. Lake outlines are shoreline shapes from LakeList and the USGS National Hydrography Dataset; they illustrate a lake's form and are not depth or navigation charts.

WI · ranked by public data

The 23 Deepest Lakes in Florence County, Wisconsin

23 Florence County lakes are at least 50 acres with a documented maximum depth, out of 108 documented lakes in the county. Updated July 2026.

182 ft
114 acres
Florence County, WI
Sea Lion Lake
enhancedDepth mapWater data
45.88, -88.32114 acres | 82 ft max1 public access pointPanfish, Largemouth Bass
82 ft maximum depth · 114 acres · 1 public landing
275 ft
73 acres
Florence County, WI
Long Lake
enhancedDepth mapWater data
45.89, -88.1373 acres | 75 ft max0 public access pointsPanfish, Largemouth Bass
75 ft maximum depth · 73 acres · No verified public access
374 ft
195 acres
Florence County, WI
Keyes Lake
enhancedDepth mapAIS recordedWater data
45.90, -88.31195 acres | 74 ft max1 public access pointLargemouth Bass, Panfish
74 ft maximum depth · 195 acres · 1 public landing
468 ft
104 acres
Florence County, WI
Bass Lake
enhancedDepth mapWater data
45.89, -88.14104 acres | 68 ft max0 public access pointsPanfish, Largemouth Bass
68 ft maximum depth · 104 acres · No verified public access
564 ft
297 acres
Florence County, WI
Brule River Flowage
enhancedDepth map
45.95, -88.22297 acres | 64 ft max0 public access pointsSmallmouth Bass, Walleye
64 ft maximum depth · 297 acres · No verified public access
654 ft
83 acres
Florence County, WI
Middle Lake
enhancedDepth mapWater data
45.90, -88.1483 acres | 54 ft max0 public access pointsPanfish, Largemouth Bass
54 ft maximum depth · 83 acres · No verified public access
752 ft
254 acres
Florence County, WI
Patten Lake
enhancedDepth mapWater data
45.85, -88.42254 acres | 52 ft max1 public access pointPanfish, Largemouth Bass
52 ft maximum depth · 254 acres · 1 public landing
845 ft
84 acres
Florence County, WI
Lost Lake
enhancedDepth mapWater data
45.88, -88.5684 acres | 45 ft max1 public access pointSmallmouth Bass, Trout
45 ft maximum depth · 84 acres · 1 public landing
944 ft
50 acres
Florence County, WI
Seidel Lake
enhancedDepth mapWater data
45.87, -88.3550 acres | 44 ft max1 public access pointLargemouth Bass, Panfish
44 ft maximum depth · 50 acres · 1 public landing
1043 ft
183 acres
Florence County, WI
Emily Lake
enhancedDepth mapWater data
45.87, -88.28183 acres | 43 ft max1 public access pointLargemouth Bass, Walleye
43 ft maximum depth · 183 acres · 1 public landing

Rank	Lake	County	Max depth	Acres	Public access
11	North Lake	Florence	43 ft	79	1 landing
12	Bass Lake	Florence	42 ft	51	1 landing
13	Fisher Lake	Florence	42 ft	50	2 landings
14	Pine River Flowage	Florence	35 ft	123	2 landings
15	Cosgrove Lake	Florence	26 ft	76	—
16	Ellwood Lake	Florence	25 ft	130	1 landing
17	West Lake	Florence	25 ft	72	—
18	Long Lake	Florence	21 ft	353	1 landing
19	West Bass Lake	Florence	19 ft	55	1 landing
20	Lake of Dreams	Florence	15 ft	62	1 landing
21	Halsey Lake	Florence	10 ft	506	1 landing
22	Fay Lake	Florence	10 ft	272	1 landing
23	Reisner Lake	Florence	5 ft	96	—

Methodology

How this list is built

Ranked strictly by documented maximum depth from DNR lake records. No estimates, no hearsay depths.
Lakes without a documented maximum depth are excluded rather than guessed at.
Lakes under 50 acres — or without documented acreage — are excluded from rankings.
Public access is shown for every lake but never affects the ranking — a deep lake ranks whether or not you can launch on it.

FAQ

Florence County lake records

What is the deepest lake in Florence County?

Sea Lion Lake — Sea Lion Lake in Florence County is the deepest documented lake in Florence County, at 82 feet maximum depth.

Deepest lakes statewide Biggest lakes in Florence County Clearest lakes in Florence County Lakes with the most public access in Florence County All Florence County lakes

The 23 Deepest Lakes in Florence County, Wisconsin

Sea Lion Lake

Long Lake

Keyes Lake

Bass Lake

Brule River Flowage

Middle Lake

Patten Lake

Lost Lake

Seidel Lake

Emily Lake

How this list is built

Florence County lake records

What is the deepest lake in Florence County?

The 23 Deepest Lakes in Florence County, Wisconsin

Sea Lion Lake

Long Lake

Keyes Lake

Bass Lake

Brule River Flowage

Middle Lake

Patten Lake

Lost Lake

Seidel Lake

Emily Lake

How this list is built

Florence County lake records

What is the deepest lake in Florence County?