Answer:
Thomas Jefferson acquired an interest in western exploration early in life. ... While president, Jefferson successfully acquired the Louisiana Territory from France in 1803 and sent the Lewis and Clark Expedition (1803–1806) on a mapping and scientific exploration up the Missouri River to the Pacific.
That westward expansion was greatly aided by the completion of the Transcontinental Railroad in 1869, and passage of the Homestead Act in 1862.
In the mid-19th century, the quest for control of the West led to the annexation of Texas and the Mexican–American War. ... This expansion led to debates about the fate of slavery in the West, increasing tensions between the North and South that ultimately led to the collapse of American democracy and a brutal civil war.
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