Pawtucket Falls, a waterfall and rapids on the Merrimack River in Lowell, was a defining natural feature of the site because the river drops 32 feet in less than a mile. Its name comes from an Algonkian term meaning “at the falls in the river,” and long before Lowell, the falls were an important Pennacook fishing ground. The site later helped determine the Massachusetts–New Hampshire boundary in 1740. Because the falls hindered travel, the Pawtucket Canal was built in the late 18th century. In the 1820s, the falls, canal, and waterpower led to Lowell’s founding as America’s first planned factory town and powered its textile mills for about 30 years.