Chelmsford /ˈtʃɛlmsfərd/ is a town in Middlesex County, Massachusetts in the United States. As of the 2010 United States Census, the town's population was 33,802. Only 48.4% are male and the median age of residents in Chelmsford is 39.2 years old. It is located 24 miles (39 km) northwest of Boston and, bordering on the city of Lowell, is part of the Greater Lowell metropolitan area. Besides Lowell on its northeast, Chelmsford is surrounded by four towns: Tyngsborough to the north, Billerica to the southeast, Carlisle to the south, and Westford to the west. Chelmsford is bordered by two sizable rivers: the Merrimack River to the north, and the Concord River to the east.
Named after Chelmsford in Essex,England, the town was incorporated in May 1655 by an act of the Massachusetts General Court. When Chelmsford was incorporated, its local economy was fueled by lumber mills, limestone quarries and kilns. The farming community of East Chelmsford was incorporated as Lowell in the 1820s; over the next decades it would go on to become one of the first large-scale factory towns in the United States because of its early role in the country's Industrial Revolution. Chelmsford experienced a drastic increase in population between 1950 and 1970, coinciding with the connection of U.S. Route 3 in Lowell to Massachusetts Route 128 in the 1950s and the extension of U.S. Route 3 from Chelmsford to New Hampshire in the 1960s.
Chelmsford has a representative town meeting form of government. The current town manager is Paul Cohen. The town has one public high school – Chelmsford High School, which is ranked among the top 500 schools in the nation – as well as two middle schools, and four elementary schools. The charter middle school started in Chelmsford became a regional charter school (Innovation Academy Charter School) covering grades 5 through 12, now located in Tyngsborough. Chelmsford high school age students also have the option of attending the Nashoba Valley Technical High School, located in Westford. In 2011, Chelmsford was declared the 28th best place to live in the United States by Money magazine.