The Coignet Stone Company Building is a historical structure in the Gowanus neighborhood of Brooklyn in New York City, at the intersection of Third Street and Third Avenue. Designed by architects William Field and Son and constructed between 1872 and 1873, it is the city's oldest remaining concrete building. The Coignet Building is the last remaining structure of a five-acre concrete factory complex built for the Coignet Agglomerate Company along the Gowanus Canal.

Litchfield Villa, or "Grace Hill", is an Italianate mansion built in 1854–1857 on a large private estate now located in Prospect Park, Brooklyn, New York City. It is located on Prospect Park West at 5th Street. The villa was designed by Alexander Jackson Davis, America's leading architect of the fashionable Italianate style, for railroad and real estate developer Edwin Clark Litchfield.