What war was fought in the 1800s in the US?

Answer 1

The United States was involved with several wars in that century. The "big one" was the Civil War, started in 1861.

Answer 2

{| |- | There were numerous wars in and around the US and US territories. The War of 1812 which was fought on the US soil. The American Civil War was entirely fought in the US. The Spanish American War and the Mexican American War both occurred during this time frame, but little activity on American soil. |}