The First Republic of Korea was the government of South Korea from August 1948 to April 1960. The first republic was founded on 15 August 1948 after the transfer from the United States Army Military Government that governed South Korea since the end of Japanese rule in 1945, becoming the first independent republican government in Korea. Syngman Rhee became the first president of South Korea following the May 1948 general election, and the National Assembly in Seoul promulgated South Korea's first constitution in July, establishing a presidential system of government.

South Korea, officially the Republic of Korea (ROK), is a country in East Asia. It constitutes the southern part of the Korean Peninsula and borders North Korea along the Korean Demilitarized Zone; though it also claims the land border with China and Russia. The country's western border is formed by the Yellow Sea, while its eastern border is defined by the Sea of Japan. South Korea claims to be the sole legitimate government of the entire peninsula and adjacent islands. It has a population of 51.96 million, of which roughly half live in the Seoul Capital Area, the ninth most populous metropolitan area in the world. Other major cities include Incheon, Busan, and Daegu.