Name one war fought by the United States in the 1800s.

The Civil War is one of the most significant conflicts in American history, fought between 1861 and 1865. This war was primarily centered around issues such as states' rights, economic disparities, and, most critically, the institution of slavery. The Northern states (the Union) opposed secession and sought to preserve the Union, while the Southern states (the Confederacy) were fighting for their independence and the preservation of their way of life, which heavily relied on slave labor.

The impact of the Civil War was profound, leading to the end of slavery with the passage of the 13th Amendment and setting the stage for significant social and political changes in the United States during the Reconstruction Era. In contrast, the other wars listed occurred either later than the 1800s or involved different contexts and motivations, making the Civil War distinctly representative of that century.