Chestnut Hill is an affluent New England village located six miles (9.7 km) west of downtown Boston, Massachusetts, United States. Like all Massachusetts villages, Chestnut Hill is not an incorporated municipal entity. Unlike most Massachusetts villages, it encompasses parts of three separate municipalities, each located in a different county: the town of Brookline in Norfolk County; the city of Boston in Suffolk County (parts of its neighborhoods of Brighton and West Roxbury), and the city of Newton in Middlesex County. Chestnut Hill's borders are roughly defined by the 02467 ZIP Code. Chestnut Hill is not a topographical designation; the name refers to several small hills that overlook the 135-acre (546,000 m2) Chestnut Hill Reservoir rather than one particular hill. Chestnut Hill is best known as the home of Boston College, part of the Boston Marathon route, as well as the Collegiate Gothic canvas of landscape architect Frederick Law Olmsted.
While most of Chestnut Hill remained farmland well into the early 20th century, the area around the reservoir was developed, in 1870, by landscape architect Frederick Law Olmsted, designer of Central Park in New York City and of the Emerald Necklace in Boston.and Brookline.
Because of the significance of its landscape and architecture, the National Register of Historic Places, in 1986, designated parts of Chestnut Hill as historic districts. Examples of Colonial, Italianate, Shingle, Tudor Revival, and Victorian architectural styles are evident in the village's country estates and mansions. The Boston College campus is itself an early example of Collegiate Gothic architecture.