In what battle did the United States defeat, for the first time, Communist Chinese Forces?

The Battle of Chosin Reservoir is recognized as the first significant engagement in which U.S. forces defeated Chinese Communist troops during the Korean War. This intense battle took place from late November to December 1950, where the U.S. Marine Corps, alongside U.N. forces, found themselves in a harsh environment against a numerically superior Chinese army. Despite being surrounded and outnumbered, the Marines executed a remarkable fighting withdrawal, inflicting considerable casualties on the Chinese forces, which marked a pivotal moment in the conflict.

In contrast, while the Korean War encompasses multiple battles, the Chosin Reservoir specifically is regarded for the U.S. forces' successful defiance against the Chinese Communist forces. The other battles listed, such as Iwo Jima, Guadalcanal, and the broader conflict of the Korean War itself, did not represent the first engagement where U.S. forces achieved victory against Communist Chinese forces. Thus, selecting Chosin Reservoir highlights a crucial event that established U.S. resolve and effectiveness against this new enemy.