Question 100: Name one war fought by the United States in the 1900s.
Official answers (any one counts)
USCIS accepts any of these answers. If the question asks for more than one, give as many as it asks.
- World War I
- World War II
- Korean War
- Vietnam War
- (Persian) Gulf War
Grandpa explains
The 1900s had five: both World Wars, Korea, Vietnam, and the Persian Gulf. One is enough, kiddo.
Careful: these are NOT the answer
These are the common mix-ups. The app uses them as traps so you practice.
- Civil War
- Revolutionary War
- War of 1812
On the 2008 test this is question 78
If you filed your N-400 before October 20, 2025, you take the 2008 version. Which one is mine?
Name one war fought by the United States in the 1900s.
★ 65/20 Also one of the 20 for 65/20 on the 2008 test.
- World War I
- World War II
- Korean War
- Vietnam War
- (Persian) Gulf War
Video lesson on this topic: The 1900s and Today
More questions on this topic
- 101Why did the United States enter World War I?
- 102When did all women get the right to vote?
- 103What was the Great Depression?
- 104When did the Great Depression start?
- 105Who was president during the Great Depression and World War II?
- 106Why did the United States enter World War II?
Official sources:
- USCIS · 128 Civics Questions and Answers (2025 version), M-1778 (09/25) ↗ · checked October 6, 2026
The plain explanation is ours; the official answers are USCIS's, word for word.