New York State Route 33A (NY 33A) is an east–west state highway mostly located in Monroe County, New York, in the United States. The route is just over 17 miles (27 km) long and serves as an alternate route of NY 33 between the town of Bergen in Genesee County and the city of Rochester in Monroe County. While NY 33 heads to Rochester by way of Churchville and northern Gates, NY 33A dips south to pass through Chili and southern Gates. NY 33A was assigned as part of the 1930 renumbering of state highways in New York, but only from Riga to Rochester. It was extended westward to its current terminus in Bergen c. 1932.

Monroe County is a county in the U.S. state of New York, located along Lake Ontario's southern shore. As of 2022, the population was 752,035, according to Census Bureau estimates. Its county seat and largest city is Rochester. The county is named after James Monroe, the fifth president of the United States. Monroe County is part of the Rochester, NY Metropolitan Statistical Area. The county is part of the Finger Lakes region of the state.