A quick search lists The Milwaukee Mile (2 mile road course) and Road America (4 mile road course) in Wisconsin. There is a 1.3 mile course at Iowa Speedway and a 2.23 mile course at Mid America Motorplex in Iowa. A 3 mile course at Brainerd International Raceway in Minnesota. A 1.8 mile at Memphis Motorsport Park and a 1.8 mile course at Nashville Superspeedway in Tennessee. Heartland Park has a road course in Topeka, Kansas. I think there is a road course near Hastings, Nebraska (Motorsports Park Hastings). And, there is Hallett Motor Racing Circuit near Tulsa, Oklahoma.
Most of these tracks run under SCCA sanctioning.
Steve