Lowell is a city of Middlesex County in Masachusetts. It is also known as the cradle of industrial revolution in the nation. Lowell is the fourth largest city in the state. It is the County seat of Middlesex. There are a number of historical sites in and around the city and chief among them is the preserved National Park Service. Lowell has a total area of about 15 sq. miles. Now the economy is primarily based on the service sector.