Crater Lake is 1,943 feet deep, making it the record holder in the U.S.:
Benjamin Grant has more in his overview:
Crater Lake is located in Fort Klamath, Oregon, USA. The awe-inspiring, deep blue water sits in a crater that was formed 7,700 years ago by the collapse of a volcano. Rain and snowfall compensate for any evaporation as no rivers flow into or out of the crater.
I once rode a bike around the 33-mile Rim Dive that encircles the lake, and one of the most notable parts of the landscape is one of its smallest—a spooky tree trunk that’s been floating vertically in the lake for more than a century:
The first record of the Old Man’s presence was made by Joseph S. Diller in 1896. According to his records, the strange, vertically floating log was splintered and bleached white, measured approximately two feet in diameter, and, at four feet above the water line, was substantial enough for a man to stand on. Moreover, the crystal clear water showed that the former tree’s roots were still intact below, making the Old Man appear rooted to the spot, despite Diller having spotted the stump a second time over a quarter-mile from its original location!
To this very day, all of the above remain true.
In the subsequent century, a few more details have emerged. Scientists believe the 30-foot long hemlock was washed into the lake via landslide, though debate continues to rage over the exact mechanics pertaining to the tree's vertical positioning. The most-accepted theory is that the tree once had rock tangled within its roots. By the time the roots decayed enough to drop the rocks, the wood beneath the waterline had absorbed water, whereas the four feet of trunk above water had dried out, thereby creating the unique, perpetually upright orientation!
(See all Orbital Views here)