Text size:

Legacy: Kettlehole Lakes

Lake Ronkonkoma is the largest of dozens of so-called "kettlehole lakes" that were formed on Long Island by the last glacier, which left the region about 20, 000 years ago. Geologist believe the lakes were formed from large chunks of ice left behind by the receding ice sheet. When those pieces of ice finally melted, they left depressions in the sandy soil that were deep enough to be filled in by the slowly rising water table. Lake Success in Nassau County is another kettlehole.