How deep is Long Lake?

Long Lake reaches a maximum depth of 35 feet in the Indiana DNR Lake Bathymetry survey. Most of it is far shallower: the survey charts 7 closed depth contours over about 110 acres, and half of that water sits inside the 15 ft line.

Where is the deepest part of Long Lake?

The deepest charted water on Long Lake lies inside the 35 ft contour, toward the southern end 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 15 feet?

About half. The 15 ft contour encloses 55 acres of the roughly 110 acres inside the outer 5 ft line, so the other half of the water is shallower than 15 feet. The sharpest drop is between 10 and 15 feet, where the mapped water sheds 29 acres.

How accurate is this Long Lake depth map?

The contours come from the Indiana DNR Lake Bathymetry 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. Per Indiana DNR, the data are graphical representations for reference only, not a survey instrument. Acreages are computed from the published contour geometry, not from a separate area survey, so read them as close approximations.

Indiana lake depth maps

Long Lake depth map

Long Lake in Steuben County, Indiana reaches a depth of 35 feet. Long Lake is charted here across 7 closed depth contours, from the 5 ft line down to 35 ft, enclosing about 110 acres of water. Half of that water lies inside the 15 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: Indiana DNR Lake Bathymetry (credit: Indiana DNR). Contours closed, checked and area-computed by Jordan Carter, founder of GilledIt · page updated August 19, 2026

Long Lake depth chart: 7 depth contours from 5 to 35 ft

Data: Indiana DNR Lake Bathymetry (credit: Indiana DNR), 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	110 acres	100%
10 ft	84 acres	76%
15 ft	55 acres	50%
20 ft	30 acres	27%
25 ft	23 acres	21%
30 ft	3.8 acres	3.4%
35 ft	under 1 acre	under 1%

Acreages are computed from the closed Indiana DNR Lake Bathymetry contour rings, with islands subtracted. Shares are of the 110 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: an evenly graded bottom

Inside its outermost 5 ft contour the survey charts about 110 acres of Long Lake, with the 15 ft line enclosing half of it, so the bottom loses depth gradually and evenly, with no broad shelf and no single abrupt drop. The sharpest change on the chart is between 10 and 15 ft, where the mapped water loses 29 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 35 ft contour there is under an acre of water, toward the southern end 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 35 ft, so structure does the thermocline's work: the points and inside turns where the 10 and 15 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 35 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 35 ft hole, 0.5 acres of it, at first light, then move up onto the 10–15 ft break as the sun gets up, and fish the flats inside the 15 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 reaches a maximum depth of 35 feet in the Indiana DNR Lake Bathymetry survey. Most of it is far shallower: the survey charts 7 closed depth contours over about 110 acres, and half of that water sits inside the 15 ft line.
Where is the deepest part of Long Lake?: The deepest charted water on Long Lake lies inside the 35 ft contour, toward the southern end 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 15 feet?: About half. The 15 ft contour encloses 55 acres of the roughly 110 acres inside the outer 5 ft line, so the other half of the water is shallower than 15 feet. The sharpest drop is between 10 and 15 feet, where the mapped water sheds 29 acres.
How accurate is this Long Lake depth map?: The contours come from the Indiana DNR Lake Bathymetry 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. Per Indiana DNR, the data are graphical representations for reference only, not a survey instrument. 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

Gentian/failing Lake depth map · 45 ft max · 10 mi away
Lake James depth map · 83 ft max · 12 mi away
Barton Lake depth map · 30 ft max · 13 mi away
Buck Lake depth map · 41 ft max · 14 mi away
Bell Lake depth map · 25 ft max · 14 mi away

Mapped fishing venues near Long Lake

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

Gentian/failing Lake · 10 mi away
Lake James · 12 mi away
Barton Lake · 13 mi away

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