Raritan Bay is a bay located at the southern portion of Lower New York Bay between the U.S. states of New York and New Jersey and is part of the New York Bight. The bay is bounded on the northwest by New York's Staten Island, on the west by Perth Amboy, New Jersey, on the south by the Raritan Bayshore communities in the New Jersey counties of Middlesex and Monmouth, and on the east by Sandy Hook Bay. The bay is named after the Raritans, a branch of the Lenape tribe who lived in the vicinity of the bay and its river for thousands of years, prior to the arrival of Dutch and English colonists in the 17th century.

Lower New York Bay is a section of New York Bay south of the Narrows. The eastern end of the Bay is marked by two spits of land, Sandy Hook, New Jersey, and Rockaway, Queens. The waterway between the spits connects the Bay to the Atlantic Ocean at the New York Bight. Traversing the floor of the Bay southeasterly from the Narrows to the Bight and beyond is Hudson Canyon.