Historic House Trust of New York City is a nonprofit formed in 1989 as a public-private partnership with the city's Department of Parks and Recreation, announced by Mayor Edward I. Koch and Parks Commissioner Henry J. Stern at Gracie Mansion. It advocates for and provides technical expertise to 23 publicly owned historic house museums on parkland across the five boroughs, sites that range from modest farmhouses to grand manor houses and that together draw hundreds of thousands of visitors annually. The Trust helps its member sites secure funding, addresses building maintenance and preservation needs, and supports collections management, educational programming, and accessibility improvements at properties that had previously suffered from decay and inconsistent restoration.