Question: Which river that streams westward from Pittsburgh, Pennsylvania, to Cairo, Illinois is the northern boundary of Downtown Louisville?
Sentence (from "Ohio River"): At the confluence, the Ohio is considerably bigger than the Mississippi (Ohio at Cairo: 281,500 cu ft/s (7,960 m/s); Mississippi at Thebes: 208,200 cu ft/s (5,897 m/s)) and, thus, is hydrologically the main stream of the whole river system.
Relevant evidence: No