Ice tongue in the context of "Otsego Lake (New York)"

Otsego Lake is a 4,046-acre (16.37 km) lake located in Otsego County in the U.S. state of New York. It is the source of the Susquehanna River and largest lake in Otsego County. The Village of Cooperstown is located at the lake's southern end. Glimmerglass State Park is located on the lake's northeastern shore, and includes Hyde Hall, a large mansion constructed in 1817, that overlooks the lake. The Glimmerglass Opera, opened in June 1987, is located on the western shore.

Between 10,000 and 12,000 years ago, glaciers of the Wisconsin glaciation filled the valley. Otsego Lake was formed when an ice tongue from a glacier carved out the Susquehanna River Valley. As the glaciers melted slowly, they filled in the valley they carved out. The lake takes its name from the Iroquois Indians, who inhabited the area around the lake in and before the 17th century. The name Otsego is from a Mohawk or Oneida word meaning "place of the rock", referring to the large boulder near the lake's outlet, today known as Council Rock.