Route 125 is an 18.90-mile-long (30.42 km) north–south Massachusetts state route. It runs from Interstate 93 in Wilmington to the Massachusetts-New Hampshire state line in Haverhill, where it continues as New Hampshire Route 125 through Plaistow to Wakefield, New Hampshire. After the first 1.7 miles (2.7 km), which are in Middlesex County, the rest of the route passes through Essex County.

Haverhill is a city in Essex County, Massachusetts, United States. Haverhill is located 35 miles north of Boston on the New Hampshire border and about 17 miles from the Atlantic Ocean. The population was 67,787 at the 2020 United States census.