In roughly 1842, give or take--can't trust my memory, there was a cohort of Mormons that located themselves northwest of Prairie du Chien on the Black River in Wisc Terr. You can find out a little about this from a book that can be read online by Bunnell of Winona Co. Minn. He describes Indian traders on the Mississippi at La Crosse who also sold items to these Mormons. Nauvoo was downriver in Illinois. There was a certain amount of interdependence between the frontier towns on the Mississippi, no matter what state or territory they officially lay in. The biggest towns were Prairie du Chien and St. Louis in 1830s.