Sylvan Lake is located next to the community by that name in the Town of Beekman, New York, United States.

It is an irregular rounded shape, with a 116-acre (47 ha) surface area, located near the town's southwestern border with East Fishkill.

Sylvan Lake Beach Park, a privately operated campground, is located along another shore.

Formerly a quarry used for mining, the slope is very steep and reaches maximum depth quickly near the center of the lake.

Equipment such as 7mml full body wetsuits including gloves and hood are necessary as are lights due to the murkiness of the water.

The lake has a bass population in its warmer areas, and the state Department of Environmental Conservation stocks it with 1,700 brown trout fry every spring.