How deep is Big Lake?

Big Lake reaches a maximum depth of 85 feet in the Michigan DNR Inland Lake Contours survey. Most of it is far shallower: the survey charts 11 closed depth contours over about 208 acres, and half of that water sits inside the 20 ft line. The 85 ft figure is a single recorded sounding rather than a closed contour, so the deepest line you can actually trace on the map is 80 ft.

Where is the deepest part of Big Lake?

The deepest charted water on Big Lake lies inside the 80 ft contour, toward the middle of the lake. That contour encloses 2.6 acres, 1.3% 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 Big Lake is shallower than 20 feet?

About half. The 20 ft contour encloses 84 acres of the roughly 208 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 74 acres.

How accurate is this Big 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

Big Lake depth map

Big Lake in Osceola County, Michigan reaches a depth of 85 feet. Big Lake is charted here across 11 closed depth contours, from the 5 ft line down to 80 ft, enclosing about 208 acres of water. Half of that water lies inside the 20 ft line, and only 2.6 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 August 19, 2026

Big Lake depth chart: 11 depth contours from 5 to 80 ft

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

Big Lake depth chart data: water enclosed by each contour
Depth contour	Water inside it	Share of mapped water
5 ft	208 acres	100%
10 ft	134 acres	64%
15 ft	106 acres	51%
20 ft	84 acres	40%
25 ft	64 acres	31%
30 ft	50 acres	24%
40 ft	39 acres	19%
50 ft	28 acres	13%
60 ft	16 acres	7.8%
70 ft	8.4 acres	4%
80 ft	2.6 acres	1.3%

Acreages are computed from the closed Michigan DNR Inland Lake Contours contour rings, with islands subtracted. Shares are of the 208 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 85 ft sounding, marked as a point rather than a closed contour, so it is not charted as a band.

Fishing Big Lake: a wide shallow flat over a deep hole

The survey encloses about 208 acres of Big Lake inside its 5 ft contour, and half of that water lies inside the 20 ft line, so most of this Osceola County water is shallow and the depth is concentrated in one part of the basin. Between 5 and 10 ft the mapped water sheds 74 acres in 5 ft of depth, the sharpest change on the chart, start on that band, because it is where the bottom stops being flat. 2.6 acres, 1.3% of the mapped water, lie inside the deepest 80 ft contour, toward the middle of the lake. At 85 ft this is two-story water: the basin can stay cold below the summer thermocline while warm-water fish stay up on the 5-to-20 ft ground, and the fish that move between the two do it along the 5–10 ft break at first and last light.

Ice fishing on Big Lake

Deep water like Big Lake freezes later and less evenly than the shallow lakes around it, and the winter bite sets up on the first real break, not out over the 80 ft hole. That edge is the 5–10 ft band on the chart above, where 74 acres of bottom tilt away, and panfish and walleye work up and down it through the day. By late ice the fish push back onto the 5-to-20 ft flat. Check ice thickness locally before you walk out.

Big Lake depth map FAQs

How deep is Big Lake?: Big Lake reaches a maximum depth of 85 feet in the Michigan DNR Inland Lake Contours survey. Most of it is far shallower: the survey charts 11 closed depth contours over about 208 acres, and half of that water sits inside the 20 ft line. The 85 ft figure is a single recorded sounding rather than a closed contour, so the deepest line you can actually trace on the map is 80 ft.
Where is the deepest part of Big Lake?: The deepest charted water on Big Lake lies inside the 80 ft contour, toward the middle of the lake. That contour encloses 2.6 acres, 1.3% 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 Big Lake is shallower than 20 feet?: About half. The 20 ft contour encloses 84 acres of the roughly 208 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 74 acres.
How accurate is this Big 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 Big Lake

Boyles Creek depth map · 70+ ft max · 9 mi away
Windover Lake depth map · 60+ ft max · 12 mi away
Silver Lake depth map · 52+ ft max · 12 mi away
Indian Lake depth map · 50 ft max · 12 mi away
Sunrise Lake depth map · 66 ft max · 13 mi away

Mapped fishing venues near Big Lake

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

Boyles Creek · 9 mi away
Windover Lake · 12 mi away
Silver Lake · 12 mi away

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