Something is wrong with Lake Itasca, the source of the Mississippi River

[FakeNoose]

14. I remember reading many years ago, that the creeks and streams of lower Ontario

... feed the lakes of upper Minnesota, including Lake Itaska.

Is that true? It seems like there's water everywhere in northern Minnesota, including many marshes and swamps. I don't know how geologists and map-makers can determine that the Mississippi River goes no farther north than Lake Itaska. It doesn't seem credible.

On the other hand, mining runoff can destroy freshwater lakes and rivers anywhere. I live in Pennsylvania where pollution from old mines has ruined much of our natural aquifer.