The Thousand Islands constitute an archipelago of 1,864 islands that straddles the Canada-U.S. border in the Saint Lawrence River as it emerges from the northeast corner of Lake Ontario. They stretch for about 50 miles (80 km) downstream from Kingston, Ontario. The Canadian islands are in the province of Ontario, the U.S. islands in the state of New York.
Boldt Castle – Aerial
Because of the great number of rocks and shoals just above or below the water’s surface, it is unwise to travel the waters at night, unless one stays in the main channels and has charts, a chart plotter, or knows the area well. The water is so clear in some areas, that a rocky bottom can be observed in 80 feet (24 m) of water. Before the advent of the zebra mussel, visibility of only ten to fifteen feet was usual, slightly decreasing as the years passed. Water clarity improved markedly in the mid-1990s with the arrival of zebra mussels, which feed on algae. The area has several shipwrecks, and although most of them are over 100 feet (30 m) underwater, some are a mere 15 feet (4.6 m) down and can be seen from the surface.
Geologically, the islands are located where a branch of the Canadian Shield runs south across the river to join with the Adirondacks.
Around twenty of these islands form the Thousand Islands National Park, the oldest of Canada’s national parks east of the Rockies. The park hosts campgrounds, inland walking trails, annual family events, as well as a national heritage building. The Thousand Islands-Frontenac Arch region was designated a World Biosphere Reserve by UNESCO in 2002. The U.S. islands include numerous New York state parks, including Wellesley Island State Park, and Robert Moses State Park – Thousand Islands located on an island in the St. Lawrence.