^Wisconsin 129 starts off toward the north from its southern point of beginning, October 2016.
Wisconsin Highway 129 is a short north-south bypass around Lancaster, a town in southwestern Wisconsin. As US Route 61 approaches Lancaster from the south, it swerves west to a different northward alignment to it can pass through the center of town. At the point where it swerves toward the west, a new highway stems northerly to serve as a bypass around the east side of Lancaster. That highway is Wisconsin Highway 129. Northeast of Lancaster, Highway 129 ends as US Route 61 swerves back to the east to continues toward the north. Note that Wisconsin Highways 35 and 81 are also concurrent with US Route 61 at the south end of Highway 129. This route is not even three miles long.
My photo of a route marker for Wisconsin Highway 129 shows the first northbound trailblazer by those turning away from US Route 61 southeast of Lancaster. I suppose it might also be possible that a person seeing this sign was coming from Wisconsin Highways 35 or 81, since they're also present at the south end of Highway 129. This photo was taken during a day-long trip around southwestern Wisconsin in October 2016.