Originally Posted by mre5765

Wind is a far bigger issue in DEN/COS, and Dash 8s are flown that route.

If ORD has no propeller service then I suspect it is because the demand for takeoffs and landings far outstrips the supply that the O'Hare airport authority is willing to offer. Thus, a landing and takeoff together represents a much more critical resource at ORD than the other hubs, and so UA cannot afford to spend it on a plane with under 50 seats of capacity.