This paper was later cited and Finger Lakes formally used as a proper name by R. Currently, the oldest known published use of finger lakes for this group of 11 lakes is in a United States Geological Survey paper by Thomas Chamberlin that was published in 1883. The origin of the name Finger Lakes is uncertain. Though none of the lakes' widths exceed 3.5 miles (5.6 km), Seneca Lake is 38.1 miles (61.3 km) long, and at 66.9 square miles (173 km 2) is the largest in total area. Cayuga and Seneca Lakes are among the deepest in the United States, measuring 435 feet (133 m) and 618 feet (188 m), respectively, with bottoms well below sea level. The geological term finger lake refers to a long, narrow lake in an overdeepened glacial valley, while the proper name Finger Lakes goes back to the late 19th century. This region straddles the northern and transitional edge of the Northern Allegheny Plateau, known as the Finger Lakes Uplands and Gorges ecoregion, and the Ontario Lowlands ecoregion of the Great Lakes Lowlands. The Finger Lakes are a group of eleven long, narrow, roughly north–south lakes located directly south of Lake Ontario in an area called the Finger Lakes region in New York, in the United States.
