Civil War
Definition
The conflict between the Union and the Confederacy from 1861 to 1865, fought over slavery and the preservation of the United States.
Explanation
The American Civil War was a devastating conflict between the Northern states (Union) and the Southern states that seceded to form the Confederate States of America. The war lasted from 1861 to 1865 and was primarily caused by disputes over slavery and states' rights. The North fought to preserve the Union and eventually to end slavery, while the South sought independence to maintain its slave-based economy. The war resulted in approximately 620,000 deaths and the destruction of the South's infrastructure. The Union victory preserved the United States as one nation and ended slavery. The Reconstruction period following the war brought constitutional amendments abolishing slavery and guaranteeing rights to freed slaves.
Why this matters for your test
The Civil War is a major topic on the USCIS civics test because it fundamentally shaped the United States and led to amendments abolishing slavery and guaranteeing equal protection.
Source: USCIS 128 Civics Questions (2025)