The Boston Post Road Historic District is a 286-acre (116 ha) National Historic Landmark District in Rye, New York, and is composed of five distinct and adjacent properties. Within this landmarked area are three architecturally significant, pre-Civil War mansions and their grounds; a 10,000-year-old Indigenous peoples site and viewshed; a private cemetery, and a nature preserve. It is one of only 11 National Historic Landmark Districts in New York State and the only National Historic Landmark District in Westchester County. It touches on the south side of the nation's oldest road, the Boston Post Road (US 1), which extends through Rye. A sandstone Westchester Turnpike marker "24", inspired by Benjamin Franklin's original mile marker system, is set into a wall that denotes the perimeter of three of the contributing properties. The district reaches to Milton Harbor of Long Island Sound. Two of the properties included in the National Park designation are anchored by Greek Revival buildings; the third property is dominated by a Gothic Revival structure that was designed by Alexander Jackson Davis.
This district, which also has immense archaeological significance and importance to Native American, European-American and African-American heritage, was declared a National Historic Landmark in 1993. The three-quarters-mile (1.2 km) meadow and viewshed is one of fewer than a dozen such identified Indigenous peoples sites in all of New York State. In 2005, J. Winthrop Aldrich, former assistant to six successive Commissioners of New York State Department of Environmental Conservation (1974–1994) and Deputy Commissioner New York State Office of Parks, Recreation and Historic Preservation (1994-2003; 2007–2010), attested that the District was acknowledged to be "one of New York State's finest assets", "amply deserving the rare honor of National Historic Landmark designation by the Secretary of the Interior."