Alexander Hamilton and George Washington visited the Great Falls and began to imagine the industrial potential of the area. In 1791, Hamilton and others founded the Society for Establishing Usefull Manufactures (S.U.M.) and a "raceway" was designed by Pierre Charles L'Enfant (chief architect and planner of Washington, DC) to divert water from above the falls into the area's first mill. The design was simplified by Peter Cold and went into operation in 1794 and extended in 1801 to power additional mills. A major expansion in 1828 added an upper raceway that extended to the south, then looped back to the north to connect to the existing raceway. The final modification was made in 1838 to replace the source reservoir with with a masonry dam across the river and a new channel through rock to feed the raceway. In 1876, the S.U.M. estimated the available water power at 2,108 horsepower (1.6 MW), with about 87% of that actually being harnessed. The raceway served the community for the remainder of the 19th century before being outmoded in the early 20th century. (reference)
My tour of the raceway ended at a fence surrounding the ruins of the Allied Textile Printing Facility, which has been the source of great controversy between developers who covet its lovely river views and preservationists who covet its industrial legacy.