The Flatiron District is a neighborhood in the borough of Manhattan of New York City, named after the Flatiron Building at 23rd Street, Broadway and Fifth Avenue. Generally, the Flatiron District is bounded by 14th Street, Union Square and Greenwich Village to the south; the Avenue of the Americas and Chelsea to the west; 23rd Street and Madison Square to the north; and Park Avenue South and Gramercy Park to the east.

The Flatiron Building, originally the Fuller Building, is a triangular 22-story, 285-foot-tall (86.9 m) steel-framed landmarked building at 175 Fifth Avenue in the eponymous Flatiron District neighborhood of the borough of Manhattan in New York City. Designed by Daniel Burnham and Frederick P. Dinkelberg, and sometimes called, in its early days, "Burnham's Folly", it was opened in 1902. The building sits on a triangular block formed by Fifth Avenue, Broadway, and East 22nd Street—where the building's 87-foot (27 m) back end is located—with East 23rd Street grazing the triangle's northern (uptown) peak. The name "Flatiron" derives from its triangular shape, which recalls that of a cast-iron clothes iron.