Michigan lake depth maps
Long Lake depth map
Long Lake in Iosco County, Michigan reaches a depth of 62 feet. Long Lake is charted here across 8 closed depth contours, from the 5 ft line down to 60 ft, enclosing about 492 acres of water. Half of that water lies inside the 20 ft line, and only 3.4 acres 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
Long Lake depth chart: 8 depth contours from 5 to 60 ft
Data: Michigan DNR Inland Lake Contours (public record), retrieved August 2026 · depths change over time · not for navigation
| Depth contour | Water inside it | Share of mapped water |
|---|---|---|
| 5 ft | 492 acres | 100% |
| 10 ft | 374 acres | 76% |
| 15 ft | 294 acres | 60% |
| 20 ft | 222 acres | 45% |
| 30 ft | 152 acres | 31% |
| 40 ft | 85 acres | 17% |
| 50 ft | 30 acres | 6.1% |
| 60 ft | 3.4 acres | under 1% |
Acreages are computed from the closed Michigan DNR Inland Lake Contours contour rings, with islands subtracted. Shares are of the 492 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. The survey also records a 62 ft sounding, marked as a point rather than a closed contour, so it is not charted as a band.
Fishing Long Lake: a wide shallow flat over a deep hole
About 492 acres of Long Lake sit inside the survey's 5 ft contour, and half of that water is already gone by the 20 ft line: the bulk of this Iosco County water sits on a shallow flat, with the real depth packed into one part of the basin. The steepest break on the chart runs from 5 down to 10 ft: 118 acres of bottom fall away across 5 ft there, which makes that band the first contour to work. The deepest 60 ft contour holds 3.4 acres, under 1% of the mapped water, toward the northwestern corner of the lake. 62 ft of water makes this a two-story fishery: warm-water fish hold the 5-to-20 ft ground while the basin can stay cold below the summer thermocline, and the traffic between the two runs along the 5–10 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 60 ft hole. The 5–10 ft band on the chart above is that edge: 118 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-20 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 62 feet in the Michigan DNR Inland Lake Contours survey. Most of it is far shallower: the survey charts 8 closed depth contours over about 492 acres, and half of that water sits inside the 20 ft line. The 62 ft figure is a single recorded sounding rather than a closed contour, so the deepest line you can actually trace on the map is 60 ft.
- Where is the deepest part of Long Lake?
- The deepest charted water on Long Lake lies inside the 60 ft contour, toward the northwestern corner of the lake. That contour encloses 3.4 acres, 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 20 feet?
- About half. The 20 ft contour encloses 222 acres of the roughly 492 acres inside the outer 5 ft line, so the other half of the water is shallower than 20 feet. The sharpest drop is between 5 and 10 feet, where the mapped water sheds 118 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
- Loon Lake depth map · 128+ ft max · 2 mi away
- Rifle Lake depth map · 70+ ft max · 6 mi away
- Sage Lake depth map · 80 ft max · 7 mi away
- Grousehaven Lake depth map · 54 ft max · 8 mi away
- Devoe Lake depth map · 53 ft max · 9 mi away
Mapped fishing venues near Long Lake
Long Lake in the venue directory covers access and fishing details for this water.
- Loon Lake · 2 mi away
- Rifle Lake · 6 mi away
- Sage Lake · 7 mi away
Fishing in Michigan needs a state license: Michigan fishing license guide · all Michigan venues