Route 85 is a 21.01-mile-long (33.81 km) north–south state highway in Massachusetts, United States. It passes through the heart of Boston's MetroWest region, through towns on the eastern edge of Worcester County and western edge of Middlesex County, crossing the border between the two counties four times. Throughout its entire distance, Route 85 runs parallel to I-495, never passing more than two miles from it.