when were duels outlawed in the us

Duels were outlawed in the United States piecemeal , not all at once. In practice, one of the clearest federal milestones was 1839 , when Congress banned dueling in Washington, D.C. after the Jonathan Cilley killing.

What that means

• Washington, D.C. : dueling was outlawed in 1839.

• States : many states had already outlawed it by the mid-19th century; one source notes 18 states had banned dueling by 1859.

• Military law : dueling was also prohibited in early U.S. military law, including the 1775 Articles of War and later military codes.

Plain-English answer

If you want the shortest answer, the best date is 1839 for Washington, D.C. , but the broader U.S. answer is that dueling was banned gradually by state and federal laws over the 1800s , rather than in a single nationwide ban.

Quick context

Even after laws changed, dueling did not disappear immediately, and it lingered in some regions before fading out by the early 20th century.