St. Louis River, Minnesota
If you are looking for wildlife, the St. Louis River is home to moose, timber wolves, northern pike, black crappie, and wood turtles, just to name a few of the species in the area. And that list does not even mention any of the 163 bird species that live around it too. One hundred ninety-four miles long, the river leads to Lake Superior, which is one of the largest tributaries in the Great Lakes system.
The lower side of the river is excellent for whitewater rafting too, but it was once heavily impacted by industry, leading to it becoming one of the most polluted waterways in the state. It took roughly one billion dollars to completely restore it, though there are still dams used for hydropower that interfere with the fish and increase the accumulation of mercury in their systems.