Which war was fought by the United States in the 1800s?

The War of 1812 was indeed a significant conflict fought by the United States in the 1800s. This war took place between 1812 and 1815 and was primarily fought between the United States and Great Britain. It arose from issues such as trade restrictions, the impressment of American sailors, and British support for Native American attacks against American settlers. The war is notable for events such as the burning of Washington D.C. and the writing of "The Star-Spangled Banner."

The other wars listed occurred in different timeframes: World War I began in 1914 and ended in 1918, long after the 1800s; the Vietnam War took place predominantly in the 1960s and early 1970s; and the Korean War occurred in the early 1950s. Thus, among the choices provided, the War of 1812 is the only one that fits the criteria of being fought in the 1800s.