Seneca Lake is the second longest (at 38 miles (60 km) long) of western New York's glacial Finger Lakes and has the largest volume, estimated at 4.2 trillion US gallons (16 km³) which is 50% of all the water in all the Finger Lakes. At its deepest point it is 618 feet (188 m) deep. It is also the second deepest lake in the country as far as its depth below sea level. The lake takes its name from the Seneca nation of Native Americans. At the north end of Seneca Lake is Geneva, New York, home of Hobart and William Smith Colleges and the New York State Agriculture Experiment Station, a division of Cornell University. At the south end of the lake is Watkins Glen, New York, famed for auto racing and waterfalls.

Due to Seneca Lake's unique micro-climate it is home to over 40 wineries.