The United States expedition to Korea, the Shinmiyangyo, or simply the Korean Expedition, in 1871, is the first American military action in Korea.

It takes place predominantly on and around the Korean island of Ganghwa.

The reason for the presence of the American naval force in Korea is to support an American diplomatic delegation sent to establish trade and political relations with the peninsular nation, to ascertain the fate of the merchant ship General Sherman, and to establish a treaty assuring aid for shipwrecked sailors.

When Korean shore batteries attack two American warships on June 1, 1871, a punitive expedition is launched ten days later after the commanding American admiral fails to receive an official apology from the Koreans.

The isolationist nature of the Joseon Dynasty government and the assertiveness of the Americans leads to a misunderstanding between the two parties that changes a diplomatic expedition into an armed conflict.

On June 10, about 650 Americans land and capture several forts, killing over 200 Korean troops with a loss of only three dead.

Korea continues to refuse to negotiate with the United States until 1882.