New York State Route 427 (NY 427) is an east–west state highway in Chemung County, New York. It extends for 11.5 miles (18.5 km) from its western terminus at an intersection with NY 14 in the town of Southport, south of the city of Elmira, to its eastern terminus at an interchange with I-86/NY 17 in the town of Chemung. Between those two towns, the highway passes through the town of Ashland and serves the village of Wellsburg. Much of NY 427 follows the Chemung River.

Chemung County is a county in the U.S. state of New York. The population was 84,148 as of the 2020 census. Its county seat is Elmira. Its name is derived from a Delaware Indian village whose name meant "big horn". The county is part of the Southern Tier region of the state.