Near Killen, Lock Six lay about 200 feet away in 40 feet of water and served as the headquarters of a 9-lock system that carried river traffic around rapids and shoals. A 136-foot fall in the river over about 37 miles had long hindered commerce from the Appalachian area to the country’s interior, and leaders from the time of President James Monroe recognized the Shoals area as a major obstacle to national growth. Surveys in 1824 led to a canal system that opened in 1836 with 17 locks, each 120 feet long and 32 feet wide, but debris from rains and floods, problems controlling creeks flowing into the system, and lack of maintenance funds forced its closure in 1848. After the Civil War, new surveys began in 1875 for another canal under the Army Corps of Engineers, using stone largely from the Brooks Plantation, now Brooks Acres and Saddle Brook. The new canal was widened, the number of locks was reduced to 9, and Lock Six became the headquarters site. Among the engineers connected with the Muscle Shoals Canal was Lt. G. W. Goethals, later known for building the Panama Canal. The canal extended 14 1/2 miles from Lock One near Rogersville to Lock Nine near Florence, and its 9 locks had a total lift of 85 feet; it also included an aqueduct 900 feet long and 60 feet wide above Shoals Creek. Opened on November 10, 1890, the headquarters at Lock Six significantly influenced the development and growth of Killen, where workers and suppliers lived and where the headquarters area included fine two-story homes, a post office, a store, and about 40 other buildings. The locks were equipped with a telephone and a railroad, and locomotive number 5 still lies under the water. Although the improved canal was helpful, it was not fully satisfactory, and during its 28 years of operation from 1890 to 1918, technological developments made the river’s drop in elevation useful for generating electricity in the Shoals area, while also promising better flood control and navigation through high dam construction. Wilson Dam was built, and by 1924 the lake formed by its backwater had flooded the entire canal system. Before the water covered the site, the buildings were demolished, and lumber from them was used in some houses built in Killen in the early 1920s. Today, remnants of the canal era survive in drill marks on the rock lifts along the river’s north side, and in dry years with low water, the tops of a few canal walls can still be seen.