Lake George, nicknamed the Queen of American Lakes, is a long, narrow oligotrophic lake located at the southeast base of the Adirondack Mountains, in the northeastern portion of the U.S. state of New York. It lies within the upper region of the Great Appalachian Valley and drains all the way northward into Lake Champlain and the St. Lawrence River drainage basin. The lake is situated along the historical natural (Amerindian) path between the valleys of the Hudson and St. Lawrence Rivers, and so lies on the direct land route between Albany, New York, and Montreal, Quebec, Canada. The lake extends about 32.2 mi (51.8 km) on a north–south axis, is 187 ft (57 m) deep, and ranges from one to three miles in width, presenting a significant barrier to east–west travel. Although the year-round population of the Lake George region is relatively small, the summertime population can swell to over 50,000 residents, many in the village of Lake George region at the southern end of the lake.

The Trophic State Index (TSI) is a classification system designed to rate water bodies based on the amount of biological productivity they sustain. Although the term "trophic index" is commonly applied to lakes, any surface water body may be indexed.