Duluth Ship Canal — Wikipedia

The Duluth Ship Canal is an artificial canal cut through Minnesota Point, providing direct access to Duluth harbor from Lake Superior. Begun privately in 1871, it was put under federal supervision and maintenance several years later. It is still an important component of the harbor facilities. In its current configuration, the canal is defined by a pair of breakwaters 1,720 feet (520 m) long and 300 feet (91 m) apart, constructed of concrete set on timber and stone cribbing. The canal is maintained at 245 feet (75 m) wide and 28 feet (8.5 m) LWD, allowing passage of ocean-going ships....