^Wisconsin 145 just west of Wisconsin 57 in Milwaukee, September 2025.
Wisconsin Highway 145 runs northwest out of downtown Milwaukee, to end in Richfield, at the very northwest corner of Milwaukee's metropolitan area. It begins as a surface arterial, then it becomes a freeway. Lastly, when it reaches the Interstate 41 corridor, it becomes a surface alternate to that Interstate for a while. Wisconsin 145 begins at US Route 18, where 6th Street meets Kilbourn Avenue. Wisconsin 145 goes north for a short while on 6th Street before turning onto Fond du Lac Avenue, which will comprise most of the state highway. Fond du Lac Avenue angles northwesterly, aiming toward the city Fond du Lac, though this state highway never comes close to reaching the city. The northwestern end of Wisconsin 145 meets Interstate 41 just north of its split with US Route 45. As such, the state highway meets an interchange with US Route 45 just before its final junction with Interstate 41.