Ansan is a city in Gyeonggi Province, South Korea. It lies south of Seoul, and is part of the Seoul National Capital Area. It is connected to Seoul by rail via Seoul Subway Line 4.
Ansan is situated on the coast of the Yellow Sea (locally called West Sea). Portions of various Yellow Sea islands lie within its jurisdiction. The largest and best-known of these is Daebu Island.
Several institutions of higher learning are located in Ansan. They include Ansan College, Ansan College of Technology, Seoul Institute of the Arts, and a campus of Hanyang University.
The city is also home to National League soccer club Ansan Hallelujah.
In 1986, some towns of Hwaseong county were incorporated and Ansan city was formed. Now there are two districts because the population of Ansan city has surpassed 500,000. In Nov. of 2002, Danwon district shaped with 13 dongs and Sangnok district with 11 dongs.