^Wisconsin 188 reassurance marker seen by those turning off of US Route 12, August 2015.
Wisconsin Highway 188 is a route from Sauk City to Lake Wisconsin, just north of the Madison area. The route starts across the river from Sauk City, at US Route 12. Wisconsin Highway 188 heads northeastward from there, on the east side of the Wisconsin River. The northeastern end is at the southern access to the Merrimac Ferry. At that location, Wisconsin Highway 113 puts an end to Wisconsin Highway 188, then it jumps on the ferry northward across the Wisconsin River.