Chestnut Hill is a village located six miles (10 km) west of downtown Boston, Massachusetts, United States. It is best known for being home to Boston College and a section of the Boston Marathon route. Like all Massachusetts villages, Chestnut Hill is not an incorporated municipal entity. It is located partially in Brookline in Norfolk County, partially in the city of Boston in Suffolk County, and partially in the city of Newton in Middlesex County. Chestnut Hill's borders are defined by the 02467 ZIP Code. The name refers to several small hills that overlook the 135-acre Chestnut Hill Reservoir rather than one particular hill.