Pawtucket Canal, Guard Locks, Lowell, Middlesex County, MA

Significance: The Guard Locks were the first set of locks constructed in the Lowell System which are still in existence. They have, however, been altered and added to since first put into use. The Guard Locks complex now includes not only the locks, but also a sluice gatehouse dating from 1870, a navigation lock gatehouse (1881), and the Great (or Francis) Gate, a portcullis-type gate constructed in 1848-50 to keep flood waters from entering the canal system.
Unprocessed Field note material exists for this structure: FN-3
Survey number: HAER MA-2-A
Building/structure dates: 1792- 1796 Initial Construction
Building/structure dates: 1798 Subsequent Work
Building/structure dates: 1803 Subsequent Work
Building/structure dates: 1822-1823 Subsequent Work
Building/structure dates: 1832 Subsequent Work
Building/structure dates: 1839 Subsequent Work
Building/structure dates: 1848-1850 Subsequent Work
Building/structure dates: 1870 Subsequent Work
Building/structure dates: 1881-1900 Subsequent Work