In what year did seven southern states secede from the Union?

The correct response is the year 1861, as this is when seven southern states officially seceded from the Union, leading to the formation of the Confederate States of America. The states that seceded were South Carolina, Mississippi, Florida, Alabama, Georgia, Louisiana, and Texas, with South Carolina being the first to secede on December 20, 1860.

The year 1857 is not relevant to the secession, as it predates these events. While 1860 saw the initial actions and rhetoric around secession begin to intensify—most notably with South Carolina's decision—1861 marks the formal start of that process when additional states joined in secession throughout the early months of that year. The year 1865 is significant as it marks the end of the Civil War and the restoration of the Union, rather than the act of secession itself. Therefore, focusing on the correct year in which the significant historical event of secession occurred is essential for understanding this critical period in American history.