The image looks downstream along the Chesapeake & Ohio Canal to Lock 27, known as Spinks Ferry Lock and, in nineteenth-century records, as Campbell’s Lock. Completed in 1832, Lock 27 is located three-quarters of a mile downstream from the Monocacy Aqueduct. The coping (the stones capping the upper edges of the lock) is comprised of high quality red sandstone from the Seneca quarry. The lock itself is built of red sandstone sourced from a quarry 2.5 miles downstream from Point of Rocks, MD.
Thomas Walter, the lock’s first keeper, did much to limit the damage done during the Civil War. In September 1862, he persuaded the Confederate army, intent on halting transit on the waterway, to refrain from using explosives to destroy the Monocacy Aqueduct and Lock 27 and, instead, to drain the canal by cutting the banks (as can be seen in the rubble on both banks visible in the photograph). Walter’s actions ensured the survival of the masonry structures and of the canal as a whole. Following the war, he was discharged from the canal company for alleged collaboration with the Confederate army; however, a successful petition by witnesses and neighbors led to his reinstatement.
Lock 27 was the uppermost (and final) lock to be constructed using a design in which water entered through culverts positioned within its walls. In subsequent locks (built post-1830), bypass flumes replaced culverts altogether. Later still (circa 1870), the upper end of the lock was doubled in length in order to allow two boats to be raised or lowered at a time.