New York State Route 27A (NY 27A) is a state highway between Massapequa in Nassau County and Oakdale in Suffolk County, on Long Island, New York, in the United States. Its two most prominent components are Merrick Road and Montauk Highway.

New York State Route 27 (NY 27) is a 120.58-mile (194.05 km) long state highway that runs east–west from Interstate 278 (I-278) in the New York City borough of Brooklyn to Montauk Point State Park on Long Island, New York. Its two most prominent components are Sunrise Highway and Montauk Highway, the latter of which includes the Montauk Point State Parkway. NY 27 acts as the primary east–west highway on southern Long Island east of the interchange with the Heckscher State Parkway in Islip Terrace. The entire route in Suffolk, Nassau, and Queens counties were designated by the New York State Senate as the POW/MIA Memorial Highway. The highway gives access to every town on the South Shore. NY 27 is the easternmost state route in the state of New York, as well as the longest highway on Long Island.