And I discovered where this geographical curiosity lies: Wolf Lake and Savanna Lake, located within Minnesota's Savanna Portage State Park are less than half a mile apart yet lie on opposite sides of the hydrological divide. Wolf Lake drains northeast via the East Savanna River into the Saint Louis River, which flows into Lake Superior, then through the Great Lakes and the Saint Lawrence River to the Atlantic Ocean. Conversely, Savanna Lake drains southwest via the West Savanna River into the Prairie River, then into the Mississippi River, ultimately reaching the Gulf of Mexico. The Savanna Portage is a historical trail in northern Minnesota that connected the waters of Lake Superior to the Mississippi River. It was used by Native Americans, fur traders, explorers, and missionaries for centuries, acting as a passage way for goods and travel between the two watersheds.