Most lakes are shallower than people think. The average depth of Lake Champlain, for all its 120 miles, is 64 feet. Lake Erie bottoms out at 210.
Then there are the four below. Each one drops more than a quarter of a mile, and each got that way for a different reason.
Maximum depth in feet. Lake Michigan and Lake Erie are shown for comparison.
1. Crater Lake, Oregon: 1,943 feet
About 7,700 years ago, Mount Mazama, a volcano that stood around 12,000 feet tall, erupted so violently that it collapsed into itself. What was left was a caldera five to six miles across. Over several hundred years, rain and snow filled it, and today evaporation and seepage balance what falls, holding the lake at its depth.
Fed by rain and snow rather than rivers, the water is famously clear: according to the National Park Service, clarity averages a depth of 102 feet. Wizard Island, the cone near the western shore, was built by later eruptions inside the caldera.
2. Lake Tahoe, California and Nevada: 1,645 feet
Tahoe is the second deepest lake in the country, with its surface 6,225 feet up in the Sierra Nevada. Its average depth is about 1,000 feet, which is deeper than the deepest point of most lakes. The basin formed over roughly three to four million years through faulting, volcanic activity and glaciation.
The UC Davis Tahoe Environmental Research Center puts it this way: if you drained it, it would take about 600 years to refill.
Lake Tahoe 3D wood map from $99
3. Lake Chelan, Washington: 1,486 feet
Lake Chelan is the deepest lake in Washington and the third deepest in the country, a long, narrow ribbon of water about 55 miles long that reaches up into the Cascades. On a map it looks like a long crack in the mountains.
Lake Chelan UV-printed wood map $188
4. Lake Superior: 1,332 feet
Superior is the deepest and largest of the five Great Lakes. Its deepest point sits 1,332 feet down, according to NOAA’s Great Lakes Environmental Research Laboratory. Together, the Great Lakes hold about 21 percent of the world’s surface fresh water.
Lake Superior 3D wood map $375
What all that depth looks like in wood
On a depth map, every layer is a depth contour: a line connecting every point at the same depth below the surface. A shallow lake might only need a few. A lake like Crater or Tahoe drops away in a stack of steps, and the walls of the basin show up as tight bands of layers right off the shore. Run a finger from the beach to the middle and you can feel the bottom fall away.
If you want to know more about how those contours are drawn in the first place, start with What Is a Bathymetric Map?
Keep reading: Crater Lake: How America's Deepest Lake Was Made · Lake Tahoe by the Numbers · The Great Lakes by the Numbers
Sources: National Park Service (Crater Lake), UC Davis Tahoe Environmental Research Center (Lake Tahoe), Encyclopaedia Britannica (Lake Chelan), NOAA Great Lakes Environmental Research Laboratory and the EPA (Great Lakes), Lake Champlain Basin Program (Lake Champlain).