The Korea Transportation Safety Authority, a government agency, has also been headquartered in Ansan since June 3, 2002.

[5] In 2021, Ansan was selected as the largest residential area for foreigners and it is seeking designation as a special multicultural city.

The first humans in Ansan were in the New Stone Age, and many shell middens and prehistoric remains were found at Oido, Sihwaho, Chojidong and Daebudo.

[12][13] Not much evidence or antiquities survive from the Proto-Three Kingdoms and Samhan periods are in Ansan and nearby areas.

[9]: 29  The Mahan confederacy in Chen Shou in Records of the Three Kingdoms preserves writings about the chiefdom state.

In the Later Three Kingdoms era, the Ansan area was owned by Taebong (also known as Hugoguryeo, "Later Goguryeo") in Silla Hyogong's 4th year (AD 900).

Taejo's 5th year (AD 1396), Ansan-eoso (meaning Ansan fishery) that is now under the direct control of a detached building of Saongwon (the Department of foods and meals in the Joseon dynasty) was set up.

This region produced high-quality salt from ancient times and valuable marine products.

[19] On land, the city boundaries is marked by the town of Gunpo to the east of Ansan, Anyang to north-east, Siheung to the north and Hwaseong to the south.

Ansan has a monsoon-influenced humid continental climate (Köppen: Dwa) with cold, dry winters and hot, rainy summers.

According to the South Korean Ministry of Justice, Ansan's Danwon District is the district which has the largest foreign population in Korea, with 68,119 residents followed by Siheung (66,103), Hwaseong (59,942), Yeongdeungpo-gu, Seoul (48,682), Guro-gu, Seoul (48,343), Pyeongtaek (42,243), and Asan, South Chungcheong (35,567 people).

Previously, the first railroad in the city was the Suin Line which was opened by Korea under Japanese rule.

But the Ministry of Land, Infrastructure and Transport is extended to Goyang through Gimpo International Airport station.

It will take only 30 minutes from Yeouido to Ansan[24][25] Also, the Ministry of Land, Infrastructure and Transport is considering to extend to Seoul Station.

[28] However, due to high cost for maintenance, Ansan discontinued the public bicycle service in 2021.

Ansan West Elementary School [ko] in Wongok-dong has a multicultural program with students from other countries, a rarity in South Korean education.

[39][40][41] In the past, Ansan had fewer attractions and a poor reputation due to its industrial and fishing roots, but the east side of the city has recently experienced several beautification projects.

The canal systems which bisect the city have bicycling and walking paths, and are covered with roses, tulips, and cherry blossoms in spring.