The Zoo Interchange is a freeway interchange on the west side of Milwaukee, Wisconsin. It forms the junction of Interstate 94 (I-94, East–West Freeway), I-894, I-41, US Highway 41 (US 41) and US 45 (Zoo Freeway). It is the busiest and one of the oldest interchanges in the state. It is nicknamed as such because of the Milwaukee County Zoo located on the northwest quadrant of the interchange. The control cities at the interchange are Downtown Milwaukee to the east, Chicago to the south, Madison to the west and Fond du Lac to the north.