Sejong (ˈshe̞ːd͡ʑoŋ; ), officially the Sejong Special Self-Governing City (), is a special self-governing city and the de facto administrative capital of South Korea.
Sejong was founded in 2007 as the new planned capital of South Korea from many parts of the South Chungcheong province and some parts of North Chungcheong province to ease congestion in South Korea's current capital and largest city, Seoul, and encourage investment in the country's central region. Since 2012, the government of South Korea has relocated numerous ministries and agencies to Sejong, but many still reside in other cities, primarily Seoul, where the National Assembly and many important government bodies remain.
Sejong has a population of 351,007 as of 2020 and covers a geographic area of 465.23 km2 (179.63 sq mi), making it the least-populous and smallest first-level administrative division in South Korea. Sejong is located in the west-central Hoseo region, bordering South Chungcheong to the west, Daejeon Metropolitan City to the south, and North Chungcheong to the east.
The construction of the city is expected to be completed in 2030, at which time 500,000 people are expected to live there.
Sejong was named in honor of King Sejong the Great, the fourth king of the Joseon Dynasty and creator of the Korean alphabet, Hangul. The city was formed by combining Yeongi County, the county of South Chungcheong Province from which the majority of the city's territory was ceded, and other counties.
In 2003, then-President Roh Moo-hyun sought to relocate the national capital of South Korea from the metropolitan city of Seoul to a new multifunctional administrative city in the center of the country. The goal was to reduce the influence and dominance of Seoul on national governance and economics, whilst promoting the regional development of other areas of the country. According to the former Interior Minister Maeng Hyung-gyu in 2012, "Sejong is a symbol of the country's efforts toward more balanced regional development," helping to decongest Seoul and spur investment in the country's central region.