In 1989, the rapid industrial growth and urbanization of Seoul prompted the construction of five new cities in the Seoul Capital Area: Gunpo, Anyang, Seongnam, Bucheon, and Goyang. The move was based on a national law which was intended to promote efficient regional management in the face of an increasing demand for administration. Siheung-gun was thus disbanded, and Gunpo-eup was promoted to Gunpo-si (city). Five legal dongs (neighbourhoods) fell under Gunpo's jurisdiction, although some were further sub-divided into numerous administrative dongs—for example, Sanbon-dong was split into Sanbon 1-dong and Sanbon 2-dong. At 20.70 ㎢, Gunpo maintained the smallest area of any city in South Korea.