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Great Lakes lake depth maps

How deep is Lake St. Clair?

Lake St. Clair reaches roughly 21 feet at its greatest natural depth and averages about 11 feet (approximate figures; St. Clair appears in neither the EPA nor the NOAA GLERL table), with the dredged shipping channel running considerably deeper. Our map's 25 ft contour traces that channel. Separately, the NOAA contour set behind our interactive map below reaches 25 feet at its deepest line, across 6 depth bands and 256 contour lines.

Published figures: US EPA, Physical Features of the Great Lakes

Data: NOAA National Centers for Environmental Information, Great Lakes bathymetry (public domain). Source data checked and prepared by Jordan Carter, founder of GilledIt · page updated

Lake St. Clair depth map and depth facts

Data: NOAA National Centers for Environmental Information, Great Lakes bathymetry (public domain), retrieved August 2026 · depths change over time · not for navigation

Lake St. Clair depth facts
Deepest contour on this map25 ft (6 depth bands)
Contour sourceNOAA NCEI Great Lakes bathymetry (public domain)

Reading the Lake St. Clair depth map

The contours here map whole-lake basin structure from NOAA's open-lake survey lines, which run 500 to 2,500 meters apart. That scale shows you where the shelf breaks toward deep water, how steeply the bottom falls away from your stretch of shoreline, and where the major basins sit. It will not resolve an individual reef or drop-off, so treat it as trip-planning context alongside a proper nearshore chart, not as a spot-finding tool. And a safety note that matters on water this size: conditions and ice on the open Great Lakes are not comparable to an inland lake, so never apply inland ice or small-water judgment out here.

Lake St. Clair depth map FAQs

How deep is Lake St. Clair?
Lake St. Clair reaches roughly 21 feet at its greatest natural depth and averages about 11 feet. These are approximate figures: St. Clair is not a Great Lake and appears in neither the EPA nor the NOAA GLERL physical features table. The dredged shipping channel is considerably deeper, and the 25 ft contour on our map traces it.
Where is the deepest part of Lake St. Clair?
The deepest water in Lake St. Clair lies in the middle of the lake. Note the distinction our pages keep: the deepest contour in the NOAA dataset behind our map is the 25 ft line, while the lake's published maximum lies deeper than the mapped contours reach.
How accurate is this Lake St. Clair depth map?
The contours come from the NOAA NCEI Great Lakes 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. The NOAA compilation maps open-lake survey lines spaced 500 to 2,500 meters apart, so it shows whole-lake basin structure rather than individual reefs or drop-offs.

Compare all five: Great Lakes depths compared · US fishing license guide

Depth maps for lakes near Lake St. Clair