New York State Route 9A (NY 9A) is a state highway in the vicinity of New York City in the United States. Its southern terminus is at Battery Place near the northern end of the Brooklyn–Battery Tunnel in New York City, where it intersects with both the unsigned Interstate 478 (I-478) and FDR Drive. The northern terminus of NY 9A is at U.S. Route 9 (US 9) in Peekskill. It is predominantly an alternate route of US 9 between New York City and Peekskill; however, in New York City, it is a major route of its own as it runs along the West Side Highway and Henry Hudson Parkway. It is also one of only two signed New York State routes in Manhattan. In northern Westchester County, NY 9A follows the Briarcliff–Peekskill Parkway.

The Brooklyn–Battery Tunnel, officially the Hugh L. Carey Tunnel and commonly referred to as the Battery Tunnel or Battery Park Tunnel, is a tolled tunnel in New York City that connects Red Hook in Brooklyn with the Battery in Manhattan. The tunnel consists of twin tubes that each carry two traffic lanes under the mouth of the East River. Although it passes just offshore of Governors Island, the tunnel does not provide vehicular access to the island. With a length of 9,117 feet (2,779 m), it is the longest continuous underwater vehicular tunnel in North America.