Great Divide
Came upon this unassuming marker by the roadside near West Bend, WI:
Wisconsin Official Marker
"Great Divide
You are now on the great divide which separates the two principal drainage areas of Wisconsin. Water falling to the west of this ridge runs down the Rock River into the "Father of Waters" and after 1,400 miles reaches the Gulf of Mexico. Water which falls to the east of the ridge drains into the Milwaukee River, then down through the Great Lakes and the St. Lawrence River 2,000 miles into the Atlantic Ocean. The elevation of the divide at this point is approximately 600 feet above Lake Michigan and 1,180 feet above sea level.
Erected 1978"
I was told it's somewhat popular to take a bathroom break at the top of the ridge.