U.S.-ROK Alliance Day Date in the current year: October 1, 2024

The United States first established diplomatic relations with Korea in 1882 by signing the Treaty of Peace, Amity, Commerce and Navigation with the Joseon Dynasty of Korea. These relations were discontinued in 1905, when Korea became a Japanese protectorate under the Japan-Korea Treaty of 1905.

After the defeat of Japan in World War II, the Korean peninsula was split into two occupation zones along the 38th parallel. The northern part was occupied by the Soviet Union, and the southern part was occupied by the United States. Initial talks to establish a unified Korean state fell through, and two separate independent nations were established instead: the Democratic People’s Republic of Korea (DPRK, North Korea) and the Republic of Korea (ROK, South Korea). The United States recognized only the Republic of Korea and established diplomatic relations with the newly independent state on March 25, 1949.

On June 25, 1950, North Korea attacked South Korea following a series of border clashes and communist insurgency in South Korea. This marked the beginning of the Korean War, in which North Korea was supported by the Soviet Union and China, and South Korea was backed by the United States and other UN members.

The Korean Armistice Agreement was signed on July 27, 1953 after three years of fighting. It de facto ended the Korean War, although no peace treaty was signed and the war is de jure still ongoing. Two months after the armistice, the United States and the Republic Korea signed the Mutual Defense Treaty. By this Treaty, the two nations committed to providing mutual aid in the event of an external armed attack. The document was signed on October 1, 1953 and went into effect on November 18, 1954.

The Treaty also allowed the United States to station military forces in South Korea. United States Forces Korea was formally established within United States Indo-Pacific Command on July 1, 1957. As of 2020, the United States had over 28,000 soldiers, airmen and marines stationed in South Korea.

The Korea Defense Veterans Association (KDVA) established U.S.-ROK Alliance Day in 2021 to commemorate the signing of the Mutual Defense Treaty, highlight the importance of South Korea-United States relations, and honor the veterans who fought in the Korean War and/or have served in Korea since the signing of the Armistice Agreement. The KDVA is a non-profit organization uniting service members and veterans who served in South Korea.

U.S.-ROK Alliance Day is marked by various events such as meet & greets, webinars, round table discussions, commemorative ceremonies, veteran reunions, and more. You can support the observance by attending an event near you, posting about U.S.-ROK Alliance Day on social media, expressing your gratitude to veterans any way you can, and learning more about the Korean War and relations between the United States and South Korea.