the shortest air route is a great circle
Assuming you're driving (and not flying) the shortest route is 86 miles.
who am I
The shortest route between two points on the surface of a planet, when routes are limited to the planet's surface, is the arc of the great circle that connects the two points. The shortest route between two points anywhere, without regard to intervening matter or energy preventing the route from being followed, is always the line connecting the two points.
Great Circle Route
The fastest shortest path algorithm for finding the most efficient route between two points is Dijkstra's algorithm.
straight line
Because that location is the lowest, shortest route between oceans.
Take I-94 WEST from Milwaukee to I-494 SOUTH at EXIT 249 in Minnesota outside of St. Paul.Take I-494 SOUTH to South St. Paul.
The shortest route is on I-90 W.
2.712 km on the shortest public road route
about 1900 miles