How deep is Lake Thumb?

Lake Thumb reaches a maximum depth of 152 feet, according to the Michigan DNR Inland Lake Contours survey. Most of the lake is shallower, with 20 mapped depth bands between the shoreline and the deepest hole.

Where is the deepest part of Lake Thumb?

The deepest surveyed water on Lake Thumb sits toward the northeastern corner of the lake, inside the 152 ft contour. The interactive depth map above shows the full basin outline and the breaks leading into it.

How accurate is this Lake Thumb depth map?

The contours come from the Michigan DNR Inland Lake Contours survey. Depths change over time with water levels and sediment, so treat this map as a planning guide for fishing, and never use it for navigation.

Michigan lake depth maps

Lake Thumb depth map

Lake Thumb in Charlevoix County, Michigan reaches a depth of 152 feet. The official Michigan survey maps 20 depth bands across 43 contour lines. This free map of Lake Thumb shows every surveyed contour as an interactive depth chart you can use to plan a session before you travel.

Lake Thumb depth chart: 20 depth bands to 152 ft

Data: Michigan DNR Inland Lake Contours (public record), retrieved August 2026 · depths change over time · not for navigation

Lake Thumb depth chart data
Depth contour	Share of mapped area inside it
5 ft	about 100%
10 ft	about 86%
30 ft	about 50%
50 ft	about 26%
70 ft	about 17%
90 ft	about 9%
110 ft	about 4%
130 ft	about 1%
150 ft	under 1%

Share of the surveyed surface area enclosed by each depth contour, computed from the Michigan DNR Inland Lake Contours data.

How to fish Lake Thumb: deep, two-story water

At 152 feet, this is a two-story fishery: warm-water species work the shallows and weed edges while the deep basin can hold cold-water fish below the summer thermocline. In summer, target the transition where the bottom breaks from the shallow shelf toward the basin; fish suspend along that edge at dawn and dusk. The 20 mapped depth bands make it straightforward to find those breaks before you launch.

Ice fishing on Lake Thumb

On deep water like Lake Thumb, the winter bite concentrates along the first major drop-off rather than the deepest basin. Use the contours above to find where the shallow shelf breaks toward deep water and set up on that edge; panfish and walleye slide up and down it through the day. Late ice often pushes fish shallower again. Always verify ice thickness locally before walking out, and remember deep lakes freeze later and less evenly than shallow ones.

Lake Thumb depth map FAQs

How deep is Lake Thumb?: Lake Thumb reaches a maximum depth of 152 feet, according to the Michigan DNR Inland Lake Contours survey. Most of the lake is shallower, with 20 mapped depth bands between the shoreline and the deepest hole.
Where is the deepest part of Lake Thumb?: The deepest surveyed water on Lake Thumb sits toward the northeastern corner of the lake, inside the 152 ft contour. The interactive depth map above shows the full basin outline and the breaks leading into it.
How accurate is this Lake Thumb depth map?: The contours come from the Michigan DNR Inland Lake Contours survey. Depths change over time with water levels and sediment, so treat this map as a planning guide for fishing, and never use it for navigation.

Depth maps for lakes near Lake Thumb

Walloon Lake depth map · 100+ ft max · 14 mi away
Big Lake depth map · 81 ft max · 15 mi away
Lake Charlevoix depth map · 122 ft max · 18 mi away
Burt Lake depth map · 73 ft max · 20 mi away
Big Chub Lake depth map · 74+ ft max · 21 mi away

Mapped fishing venues near Lake Thumb

Lake Thumb in the venue directory covers access and fishing details for this water.

Walloon Lake · 14 mi away
Big Lake · 15 mi away
Gook Creek · 16 mi away

Fishing in Michigan needs a state license: Michigan fishing license guide · all Michigan venues