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
Thousand Islands throughout the year and support a living tree. Many of the islands are publicly owned. A group of 21 islands form the Thousand Islands National Park, the oldest of Canada's national parks east of the Rocky Mountains. The park hosts campgrounds, inland walking trails, annual family events, as well as a national heritage building. Thirty New York state parks are managed as part of the New York State Office of Parks, Recreation and Historic Preservation's Thousand Islands Region, including many that are located on river islands or along the New York shore. Many of these river parks were established in