<P> The role of the Federal Government in regulating interstate commerce was firmly established by the landmark Supreme Court ruling in Gibbons v Ogden, which decided against allowing states to grant exclusive rights to steamboat companies operating between states . </P> <P> President Andrew Jackson (1829--1837), leader of the new Democratic Party, opposed the Second Bank of the United States, which he believed favored the entrenched interests of rich . When he was elected for a second term, Jackson blocked the renewal of the bank's charter . Jackson opposed paper money and demanded the government be paid in gold and silver coins . The Panic of 1837 stopped business growth for three years . </P> <P> Although there was relatively little immigration from Europe, the rapid expansion of settlements to the West, and the Louisiana Purchase of 1803, opened up vast frontier lands . The high birth rate, and the availability of cheap land caused the rapid expansion of population . The average age was under 20, with children everywhere . The population grew from 5.3 million people in 1800, living on 865,000 square miles of land to 9.6 million in 1820 on 1,749,000 square miles . By 1840, the population had reached 17,069,000 on the same land . </P> <P> New Orleans and St. Louis joined the United States and grew rapidly; entirely new cities were begun at Pittsburgh, Marietta, Cincinnati, Louisville, Lexington, Nashville and points west . The coming of the steamboat after 1810 made upstream traffic economical on major rivers, especially the Hudson, Ohio, Mississippi, Illinois, Missouri, Tennessee, and Cumberland rivers . Historian Richard Wade has emphasized the importance of the new cities in the Westward expansion in settlement of the farmlands . They were the transportation centers, and nodes for migration and financing of the westward expansion . The newly opened regions had few roads, but a very good river system in which everything flowed downstream to New Orleans . With the coming of the steamboat after 1815, it became possible to move merchandise imported from the Northeast and from Europe upstream to new settlements . The opening of the Erie Canal made Buffalo the jumping off point for the lake transportation system that made important cities out of Cleveland, Detroit, and especially Chicago . </P>

What caused the areas of the united states to nearly double between 1800 and 1810