Federal Route 12 passes through Illinois only to swing around Lake Michigan. In doing so, it ends up being a generally northwest-southeast route through the Chicago area. It tends to hang onto US Routes 20 and 45 to make its way around the city.
Information on US12 is broken into 2 parts:
Wisconsin state line to US20 (at Bellwood)
Continue east to US12 in Cook County, multiplexed with US20
