The Finger Lakes, in west-central New York, got their name because their long, narrow shapes look like fingers of a hand.
There are 11 lakes in the group, although some people disagree on that number.
The largest is Lake Seneca, at 37 miles (60 km) long and 3 miles (5 km) wide at its widest point.
These lakes were formed when glaciers, which covered the state with ice that was up to 2 miles (3.2 km) thick, cut deep valleys in the area.
When those glaciers began to melt and recede about 10,000 years ago, water filled the valleys.
Glacial deposits of sand and rock kept the water from draining out of the ends of the valleys, and the lakes were created.
The long, deep Finger Lakes were cut by glaciers. Their names come from Native American words.