Ever since Illinois had been admitted in 1818, Michigan had been the one remaining territory of the old Northwest, including the whole area north of Ohio, Indiana, and Illinois, and extending from Lake Huron to the Mississippi River. Her huge size was admittedly temporary, but as no large centre of population existed outside of Detroit, it was convenient to simplify the federal jurisdiction in this fashion. The lead mines on the Mississippi produced a secondary centre of population in the late twenties and pointed to an early division of Michigan. But before this could be accomplished the Black Hawk purchase had carried the Mississippi centre of population to the right bank of the river. The American possessions on this bank, west of the river, had been cast adrift without political organization on the admission of Missouri in 1821. Now the appearance of a vigorous population in an unorganized region compelled Congress to take some action, and thus, for temporary purposes, Michigan was enlarged in 1834. Her new boundary extended west to the Missouri River, between the state of Missouri and Canada. The new Northwest, which may be held to include Iowa, Wisconsin, and Minnesota, started its political history as a remote settlement in a vast territory of Michigan, with its seat of government at Detroit. Before it was cut off as the territory of Wisconsin in 1836 much had been done in the way of populating it. The boom of the thirties brought Arkansas and Michigan into the Union as states, and started the growth of the new Northwest. The industrial activity of the period was based on speculation in public lands and routes of transportation. America was transportation mad. New railways were building in the East and being projected West. Canals were turning the western portage paths into water highways. The speculative excitement touched the field of religion as well as economics, producing new sects by the dozen, and bringing schisms into the old. And population moving already in its inherent restlessness was made more active in migration by the hard times of the East in 1833 and 1834. The immigrants brought to the Black Hawk purchase and its vicinity, in the boom of the thirties, came chiefly by the river route. The lake route was just beginning to be used; not until the Civil War did the traffic of the upper Mississippi naturally and generally seek its outlet by Lake Michigan. The Mississippi now carried more than its share of the home seekers.