You can visit parts of the Old Croton Aqueduct, which was the first major aqueduct supplying New York City. The OCA was about 41 miles long, less than half the length of the Delaware, but an impressive piece of engineering when you consider that it was built in the 1830s, with only minimal help from machinery.
Without the OCA, New York as it is today probably wouldn’t exist. At the time it was built, the city was pretty much running out of water, and the water sources that did exist were increasingly polluted. If they hadn’t been able to bring water from elsewhere, the city’s growth would probably have come to a hard stop before the second half of the 19th century.
