Highway 125 begins at a junction with US 41 and County Highway CA in the Town of Grand Chute. From here, the route heads east as a divided highway called College Avenue, passing through a business district. It meets County Highway AA (Bluemound Drive) before passing a baseball diamond. After entering Appleton, the highway meets County Highway A (Lynndale Drive). Past this junction, the route crosses the Canadian National Railway and becomes an undivided road. The highway runs through a mixed residential and business area, passing to the south of Wilson Middle School. After crossing Badger Avenue, Highway 125 terminates at a junction with Highway 47; College Avenue continues east of the intersection.Valley Transit's Route 15 West College bus serves much of Highway 125, including the entire eastern half of the road.