High Quality Content by WIKIPEDIA articles! New York State Route 426 (NY 426) is a state highway located entirely within Chautauqua County, New York, United States. It runs just over 13 miles (21 km) from one section of the Pennsylvania state line to another, passing through two small hamlets and providing the Southern Tier Expressway (NY 17 and Interstate 86 or I-86) with its westernmost exit in New York. NY 426 is the westernmost north–south state highway in New York.