The Pre-Civil War Era in the United States, spanning from the late 1820s to 1861, was marked by significant social, economic, and political changes. This period saw the rise of the abolitionist movement, which sought to end slavery, and the expansion of the railroad system, facilitating westward migration and trade. Tensions between the Northern and Southern states grew as issues like states' rights and slavery became increasingly contentious. During this time, key events such as the Missouri Compromise of 1820 and the Compromise of 1850 attempted to address the balance of power between free and slave states. The publication of Uncle Tom's Cabin in 1852 further fueled anti-slavery sentiments in the North. Ultimately, these conflicts laid the groundwork for the outbreak of the American Civil War in 1861.