ABOUT: The Upper Peninsula of Michigan is the northern of the two major land masses that make up the U.S. state of Michigan. It is commonly referred to as the Upper Peninsula (U.P.) and Upper Michigan. It is also known colloquially as the land "above the Bridge" linking the two peninsulas. The peninsula is bounded on the north by Lake Superior, on the east by the St. Marys River, on the southeast by Lake Michigan and Lake Huron, and on the southwest by Wisconsin.