to
Update
is a city in Middlesex County, Massachusetts, USA. As of the 2000 census, the city had a total population of 105,167. It is the fourth largest city in the state. It and Cambridge are the county seats of Middlesex County.
Founded as a planned manufacturing center for textiles along the Merrimack River northwest of Boston on land sectioned from neighboring Chelmsford, it was a thriving industrial center during the 19th century, attracting many immigrants and migrant workers to its mills. With the decline of its manufacturing in the 20th century, the city fell into deep hard times but has begun to rebound in recent decades. The former mill district along the river is partially restored and is a part of the Lowell National Historical Park.