Named after Ninth Avenue, near the old line between two Dutch towns.
The station stands at Ninth Avenue and 39th Street. The Dutch towns of Brooklyn and New Utrecht were divided by a boundary running diagonally from Seventh Avenue/60th Street to Ninth Avenue/37th Street. According to one neighbourhood guide, Ninth Avenue now marks the eastern edge of Sunset Park. North of Green-Wood Cemetery, the street now called Prospect Park West was formerly, and officially, 9th Avenue.