What are some significant transformations the us went through during 1800 to 1845?

Louisiana Purchase. 828,000 square miles of land purchased from Napoleon, leader of France, by Thomas Jefferson in 1803, War of 1812, This compromise proposed by Henry Clay in 1820 was to maintain sectional balance and allowed Missouri to enter the Union as a slave state while Maine entered free.

saint clair’s defeat, (november 4, 1791), one of the worst defeats ever suffered by u.s. forces in indian warfare, precipitated by british-indian confrontation with settlers and militia in the northwest territory following the american revolution. despite specific provisions in the treaty of 1783 for the evacuation of its forts on the northwestern border, britain had failed to yield these lucrative fur-trading posts. in hopes of reclaiming lost hunting grounds with british support, a northwest indian confederation was gradually molded between 1785 and 1787, consisting mainly of shawnee, delaware, ottawa, iroquois, ojibwa, miami, and potawatomi. kentucky frontiersmen reacted to this threat by initiating raiding parties on native villages as early as 1788, and indian warfare flared up the following year.

b) the confederacy had to pay all union war expenses.