The B46 bus route constitutes a public transit corridor in Brooklyn, New York City. The route runs primarily along Utica Avenue north from the Kings Plaza shopping center through Eastern Brooklyn, with continued service west along Broadway to the Williamsburg Bridge Plaza Bus Terminal. The corridor was originally served by a streetcar line, known as the Utica and Reid Avenues Line, Utica−Reid Line, Reid−Utica Line, Reid Avenue Line, or Utica Avenue Line until 1951, when the line was replaced by bus service. The bus route is operated by MTA Regional Bus Operations under the New York City Transit brand.

Utica Avenue is a major avenue in Brooklyn, New York City, New York, United States. It is one of several named for the city of Utica in Upstate New York. It runs north–south and occupies the position of East 50th Street in the Brooklyn street grid, with East 49th Street to its west and East 51st Street to its east for most of its path. The south end of Utica Avenue is at Flatbush Avenue; its north end is at Fulton Street, beyond which it is continued by Malcolm X Boulevard in Bedford–Stuyvesant. Malcolm X Boulevard continues to Broadway, where it terminates on Broadway between Lawton Street and Hart Street.