Name one war fought by the United States in the 1900s.

Answers from the USCIS list

Give one of these answers. Words in light (parentheses) are optional.

• World War I
• World War II
• Korean War
• Vietnam War
• optional: (Persian) Gulf War

Our explanation

The 1900s means the years 1900 to 1999. U.S. wars in those years include World War I, World War II, the Korean War, the Vietnam War, and the Persian Gulf War.

Remember it

Two World Wars, then K-V-G: Korea, Vietnam, Gulf.

Source

USCIS 2025 Study Guide (One Nation, One People, M-1175) p. 63: “World War I is one war fought by the United States in the 1900s.” … “Other wars … World War II, Korean War, Vietnam War, (Persian) Gulf War”.

• 128 Civics Questions and Answers (2025 version), M-1778 (09/25) (PDF, USCIS)

Last checked on September 29, 2026.

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Easy to mix up with

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