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

What does this answer mean?

The United States fought several wars in the 1800s, and you only need to name one. USCIS accepts four: the War of 1812, the Mexican-American War, the Civil War, or the Spanish-American War.

The War of 1812 was fought against Britain from 1812 to 1815, while James Madison was president. One of the main issues was Britain forcing sailors from American ships into its navy.

The Mexican-American War was fought against Mexico in the 1840s. The treaty that ended it, the Treaty of Guadalupe Hidalgo, gave the United States a large area of land in the West.

The Civil War, from 1861 to 1865, was fought between the North and the South, and it ended slavery. It's the subject of several other questions on the test.

The Spanish-American War was fought against Spain in 1898.

At the interview, an easy answer is "the Civil War," since you'll study it for other questions anyway.