Lowell, at the confluence of the Merrimack and Concord rivers (which Thoreau wrote about so memorably), has a rich history in textiles. Founded in 1826 as a mill town using water power, it was named after Boston's Francis Cabot Lowell, a major figure in the Industrial Revolution who had prospered in the China Trade. Indeed, the city became one of the cradles of the American Industrial Revolution because of its many factories, most of which were textile mills. Also giving the city a certain romance is its canal network, on which you can travel by tourist boat.
In the late 20th Century some of Lowell's historic manufacturing sites became part of the Lowell National Historical Park. It's well worth a visit. During the Cambodian genocide by the Communist Khmer Rouge in the '70s, the city took in an influx of refugees from that country, leading to the development of a section called Cambodia Town.