How deep is Long Lake?

Long Lake reaches a maximum depth of 71 feet in the Michigan DNR Inland Lake Contours survey. Most of it is far shallower: the survey charts 10 closed depth contours over about 43 acres, and half of that water sits inside the 40 ft line.

Where is the deepest part of Long Lake?

The deepest charted water on Long Lake lies inside the 71 ft contour, toward the southeastern corner of the lake. That contour encloses under an acre, 1.4% of the mapped water, so it is a small target on a small water, the depth chart above gives the contour to line up on.

How much of Long Lake is shallower than 40 feet?

About half. The 40 ft contour encloses 18 acres of the roughly 43 acres inside the outer 5 ft line, so the other half of the water is shallower than 40 feet. The sharpest drop is between 70 and 71 feet, where the mapped water sheds 2.9 acres.

How accurate is this Long Lake depth map?

The contours come from the Michigan DNR Inland Lake Contours survey, retrieved August 2026 and last rebuilt on August 19, 2026. 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. Acreages are computed from the published contour geometry, not from a separate area survey, so read them as close approximations.

Michigan lake depth maps

Long Lake depth map

Long Lake in Luce County, Michigan reaches a depth of 71 feet. Long Lake is charted here across 10 closed depth contours, from the 5 ft line down to 71 ft, enclosing about 43 acres of water. Half of that water lies inside the 40 ft line, and only under an acre lie inside the deepest one. Every contour is on the interactive map below, free and without an account.

Data: Michigan DNR Inland Lake Contours (public record). Contours closed, checked and area-computed by Jordan Carter, founder of GilledIt · page updated August 19, 2026

Long Lake depth chart: 10 depth contours from 5 to 71 ft

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

Long Lake depth chart data: water enclosed by each contour
Depth contour	Water inside it	Share of mapped water
5 ft	43 acres	100%
10 ft	35 acres	81%
15 ft	31 acres	71%
20 ft	27 acres	63%
30 ft	24 acres	56%
40 ft	18 acres	42%
50 ft	8 acres	19%
60 ft	4.8 acres	11%
70 ft	3.5 acres	7.9%
71 ft	under 1 acre	1.4%

Acreages are computed from the closed Michigan DNR Inland Lake Contours contour rings, with islands subtracted. Shares are of the 43 acres inside the outermost charted contour (the 5 ft line), which is the outer edge of the mapped water, several state files carry no 0 ft shoreline line, so this is not the same as a share of the lake's published surface area.

Fishing Long Lake: a stepped drop into deep water

Inside its outermost 5 ft contour the survey charts about 43 acres of Long Lake, with the 40 ft line enclosing half of it, so the drop to the deep basin comes in stages, each contour giving up another slice of water, rather than in one abrupt wall. The sharpest change on the chart is between 70 and 71 ft, where the mapped water loses 2.9 acres in 1 ft of depth, that band is the contour to work first, because it is where the bottom stops being flat. Inside the 71 ft contour there is under an acre of water, toward the southeastern corner of the lake: a single pocket rather than a basin, and worth a drift over in high summer. 71 ft of water makes this a two-story fishery: warm-water fish hold the 5-to-40 ft ground while the basin can stay cold below the summer thermocline, and the traffic between the two runs along the 70–71 ft break at first and last light.

Ice fishing on Long Lake

Long Lake freezes later and less evenly than the shallow waters around it, and the winter bite sets up on the first real break rather than out over the 71 ft hole. The 70–71 ft band on the chart above is that edge: 2.9 acres of bottom tilt away there, and panfish and walleye slide up and down it through the day. Late ice pushes fish back onto the 5-to-40 ft flat. Check ice thickness locally before you walk out.

Long Lake depth map FAQs

How deep is Long Lake?: Long Lake reaches a maximum depth of 71 feet in the Michigan DNR Inland Lake Contours survey. Most of it is far shallower: the survey charts 10 closed depth contours over about 43 acres, and half of that water sits inside the 40 ft line.
Where is the deepest part of Long Lake?: The deepest charted water on Long Lake lies inside the 71 ft contour, toward the southeastern corner of the lake. That contour encloses under an acre, 1.4% of the mapped water, so it is a small target on a small water, the depth chart above gives the contour to line up on.
How much of Long Lake is shallower than 40 feet?: About half. The 40 ft contour encloses 18 acres of the roughly 43 acres inside the outer 5 ft line, so the other half of the water is shallower than 40 feet. The sharpest drop is between 70 and 71 feet, where the mapped water sheds 2.9 acres.
How accurate is this Long Lake depth map?: The contours come from the Michigan DNR Inland Lake Contours survey, retrieved August 2026 and last rebuilt on August 19, 2026. 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. Acreages are computed from the published contour geometry, not from a separate area survey, so read them as close approximations.

Depth maps for lakes near Long Lake

Camp Eight Lake depth map · 74+ ft max · 0 mi away
North Belle Lake depth map · 70+ ft max · 10 mi away
Syphon Lake depth map · 160 ft max · 11 mi away
Grand Sable Lake depth map · 85+ ft max · 18 mi away
East Twin Lake depth map · 61 ft max · 21 mi away

Mapped fishing venues near Long Lake

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

North Belle Lake · 10 mi away
Syphon Lake · 11 mi away
Grand Sable Lake · 18 mi away

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