The Saint Louis River is the largest U.S. tributary to Lake Superior and forms a 12,000-acre freshwater estuary where it meets the lake. Located on the border of Minnesota and Wisconsin near Duluth and Superior, this diverse ecosystem transitions from a turbulent river with rocky substrate in its upper reaches to a complex system of sheltered bays, channels, and wetlands in the lower estuary. Once severely degraded by industrial pollution, the river has experienced remarkable recovery following the implementation of the Clean Water Act and establishment of the Western Lake Superior Sanitary District in 1978. Today, the Saint Louis River supports a productive fishery valued by recreational anglers and tribal members alike, offering opportunities to catch numerous species in settings ranging from fast-flowing river sections to placid backwaters.