Hennepin Canal: America's First Concrete Canal

The Hennepin Canal slicing across northwestern Illinois holds a quiet engineering distinction: it was the first canal in the United States built entirely of concrete, without stone-cut facings. Construction ran from eighteen ninety to nineteen oh seven, and when the first boat passed through in nineteen oh seven, it had cut the route from Chicago to Rock Island by four hundred nineteen miles.

Engineers working on the Hennepin pioneered concrete lock chambers and a feeder canal design that would later show up in the Panama Canal. Commercially the canal disappointed, arriving just as railroads made water freight obsolete. But as an engineering laboratory, it taught the nation how to build in concrete at scale. Today the entire waterway of roughly one hundred four miles is listed on the National Register of Historic Places and serves as a linear state park for hiking and cycling.