How deep is Long Lake?

Long Lake is more than 45 feet deep. The deepest contour in the Michigan DNR Inland Lake Contours survey is the 45 foot line, and the lake continues deeper inside it.

Where is the deepest part of Long Lake?

The deepest charted water on Long Lake lies inside the 45 ft contour, toward the northeastern corner of the lake. That contour encloses under an acre, under 1% 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 30 feet?

About half. The 30 ft contour encloses 24 acres of the roughly 86 acres inside the outer 10 ft line, so the other half of the water is shallower than 30 feet. The sharpest drop is between 25 and 30 feet, where the mapped water sheds 21 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 Branch County, Michigan reaches a depth of more than 45 feet at its deepest surveyed contour. Long Lake is charted here across 8 closed depth contours, from the 10 ft line down to 45 ft, enclosing about 86 acres of water. Half of that water lies inside the 30 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: 8 depth contours from 10 to 45 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
10 ft	86 acres	100%
15 ft	76 acres	88%
20 ft	63 acres	73%
25 ft	45 acres	53%
30 ft	24 acres	28%
35 ft	9.9 acres	12%
40 ft	4.1 acres	4.7%
45 ft	under 1 acre	under 1%

Acreages are computed from the closed Michigan DNR Inland Lake Contours contour rings, with islands subtracted. Shares are of the 86 acres inside the outermost charted contour (the 10 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: steep sides for its size

Inside its outermost 10 ft contour the survey charts about 86 acres of Long Lake, with the 30 ft line enclosing half of it, so depth comes quickly here, with no long shallow margin before the bottom drops away. The sharpest change on the chart is between 25 and 30 ft, where the mapped water loses 21 acres in 5 ft of depth, that band is the contour to work first, because it is where the bottom stops being flat. Inside the 45 ft contour there is under an acre of water, toward the northeastern corner of the lake: a single pocket rather than a basin, and worth a drift over in high summer. Nothing here reaches a true cold-water layer at 45 ft, so structure does the thermocline's work: the points and inside turns where the 25 and 30 ft lines pinch together fish hardest in early season, and again as fish follow bait back down in autumn.

Ice fishing on Long Lake

At 45 ft, Long Lake is a workable ice depth: deep enough to hold fish all winter without the slow freeze-up of a big basin. Start on the 45 ft hole, 0.5 acres of it, at first light, then move up onto the 25–30 ft break as the sun gets up, and fish the flats inside the 30 ft line through the middle of the day. Check ice thickness locally before you walk out.

Long Lake depth map FAQs

How deep is Long Lake?: Long Lake is more than 45 feet deep. The deepest contour in the Michigan DNR Inland Lake Contours survey is the 45 foot line, and the lake continues deeper inside it.
Where is the deepest part of Long Lake?: The deepest charted water on Long Lake lies inside the 45 ft contour, toward the northeastern corner of the lake. That contour encloses under an acre, under 1% 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 30 feet?: About half. The 30 ft contour encloses 24 acres of the roughly 86 acres inside the outer 10 ft line, so the other half of the water is shallower than 30 feet. The sharpest drop is between 25 and 30 feet, where the mapped water sheds 21 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

Coldwater Lake depth map · 90+ ft max · 2 mi away
Lake of the Woods depth map · 70+ ft max · 4 mi away
Marble Lake depth map · 60+ ft max · 6 mi away
George Lake depth map · 82 ft max · 7 mi away
Hemlock Lake depth map · 60+ ft max · 10 mi away

Mapped fishing venues near Long Lake

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

Coldwater Lake · 2 mi away
Lake of the Woods · 4 mi away
Marble Lake · 6 mi away

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