U.S. Federal Route 20 runs east-west across Winnebago County. Through out the whole county, this highway is multi-lane. Around the southside of the Rockford Metro-Area, U.S. Rt. 20 is a expressway. U.S. Rt. 20 passes through the following towns in Winnebago County. Rockford Cherry Valley U.S. Rt. 20 is multi-plexed in Winnebago County. Interstate 39, from Rockford to Cherry Valley. U.S. Rt. 51, from Rockford to Cherry Valley.