In addition to servicing Rochester, I-390 serves as an important connecting route between the Rochester metropolitan area and Corning and the rest of the Southern Tier of New York. The freeway also serves several smaller communities between Corning and Rochester, including the Livingston County villages of Dansville and Geneseo. I-390 effectively replaced U.S. Route 15 (US 15) and parallels NY 15, US 15's "de facto" successor north of Corning. From Lakeville north to Brighton, the two routes cross paths four times and are located no more than apart along the entire stretch.