Siheung Korean: [ɕʰihɯŋ] is a city in Gyeonggi Province, South Korea.In the early Three Kingdoms period, the Siheung area was part of the Baekje kingdom. It was lost to Goguryeo along with the Han River valley in 475.Siheung acquired its current administrative identity on January 1, 1989, when the old county of Siheung (Siheung County) was divided into the cities of Siheung, Gunpo, and Uiwang. At the time Siheung city had a population of only 93,000.