Boundary Waters Treaty of 1909

The Boundary Waters Treaty is the 1909 treaty between the United States, and the United Kingdom with respect to Canada, providing mechanisms for resolving any disputes over waters bordering the U.S. and Canada. The treaty covers the main shore of the lakes and rivers and connecting waterways, or the portions thereof, along which the international boundary between the United States and Canada passes, including all bays, arms, and inlets thereof, but not including tributary waters which in their natural channels would flow into such lakes, rivers, and waterways, or waters flowing from such lakes, rivers, and waterways, or canals or streams, or steams or the waters of rivers flowing across the boundary.

Source: Wikipedia — Boundary Waters Treaty of 1909 (CC BY-SA 4.0)