Zebulon Montgomery Pike explored the Mississippi River from St. Louis to its source (or what he identified as its source) in 1805 on behalf of the United States government. Here are some entries from his record of the journey as he proceeded up the river.
Sunday, Sept. 1st. Embarked early; wind fair; arrived at the lead mines [Dubuque, Ia.] at twelve o’clock. A dysentery, with which I had been afflicted several days, was suddenly checked this morning, which I believe to have been the occasion of a very violent attack of fever about eleven o’clock. Notwithstanding it was very severe, I dressed myself, with an intention to execute the orders of the general relative to this place. We were saluted with a field-piece, and received with every mark of attention by Monsieur [Julien] Dubuque, the proprietor. There were no horses at the house, and it was six miles to where the mines were worked; it was therefore impossible to make a report by actual inspection. I therefore proposed 10 queries, on the answers to which my report was founded.
Dined with Mr. D., who informed me that the Sioux and Sauteurs were as warmly engaged in opposition as ever; that not long since the former killed 15 Sauteurs, who on the 10th of August in return killed 10 Sioux, at the entrance of the St. Peters; and that a war-party, composed of Sacs, Reynards, and Puants [Winnebagos] of 200 warriors, had embarked on an expedition against the Sauteurs; but that they had heard that the chief, having had an unfavorable dream, persuaded the party to return, and that I would meet them on my voyage. At this place I was introduced to a chief called Raven, of the Reynards. He made a very flowery speech on the occasion, which I answered I a few words, accompanied by a small present.
I had now given up all hopes of my two men, and was about embark when a peroque arrived, in which they were, with a Mr. Blondeau, and two Indians whom that gentleman had engaged above the rapids of Stony [Rock] river. The two soldiers had been six days without anything to eat except muscles [Mussels], when they met Mr. James Aird, by whose humanity and attention their strength and spirits were in a measure restored; and they were enabled to reach the Reynard village, where they met Mr. B. The Indian chief furnished them with corn and shoes, and showed his friendship by every possible attention. I immediately discharged the hire of the Indians, and gave Mr. Blondeau a passage to the Prairie des Cheins. Left the lead mines at four o’clock. Distance 25 miles.
From Coues, 1895. Items in the brackets seem to be by that author.