Thousand Islands level year-round, and support at least two living trees. The Thousand Islands archipelago is located at the outlet of Lake Ontario at the head of the Saint Lawrence River. The region is bisected by the Canada–United States border and covers portions of Jefferson and St. Lawrence counties in the U.S. state of New York, in addition to parts of the United Counties of Leeds and Grenville and Frontenac County in the Canadian province of Ontario. Geologically, most of the islands are located where a branch of the Canadian Shield runs south across the river to join with the Adirondacks. The
North American river otter component of their diets. They are less likely to be prey for the North American river otters since they are fast-swimming and can find good escape cover. However, river otters will prey on trout, pike, walleye ("Sander vitreus vitreus"), salmon ("Oncorhynchus" spp.), and other game fish during spawning. Adult North American river otters are capable of consuming of fish per day. A study conducted on captive otters revealed they preferred larger fish, ranging from , more than smaller fish, ranging from , and they had difficulty catching fish species less than or larger than . Otters are known to take