U.S. Federal Route 45 is a north-south highway in Northeastern and South-Central Johnson County. U.S. Rt. 45 passes through the following towns in Johnson County. New Burnside Bloomfield Vienna U.S. Rt. 45 is not multi-plexed in Johnson County. U.S. Rt. 45 intersects the following highways in Johnson County. Illinois State Route 166, at New Burnside. Interstate 24, near Bloomfield. Illinois State Route 146, at Vienna.