Gyeonggi-do (Hangul: 경기도, Korean pronunciation: [kjʌŋ.ɡi.do]) is the most populous province in South Korea. Its name, Gyeonggi means "the area surrounding capital". Thus Gyeonggi-do can be translated as "province surrounding Seoul". The provincial capital is Suwon. Seoul—South Korea's largest city and national capital—is in the heart of the province but has been separately administered as a provincial-level special city since 1946. Incheon—South Korea's third largest city—is on the coast of the province and has been similarly administered as a provincial-level metropolitan city since 1981. The three jurisdictions are collectively referred to as Sudogwon and cover 11,730 km², with a combined population of 25.5 million—amounting to over half of the entire population of South Korea.

Gyeonggi-do has been a politically important area since 18 BCE, when Korea was divided into three nations during the Three Kingdoms period. Ever since King Onjo, the founder of Baekje (one of the three kingdoms), founded the government in Wiryeseong of Hanam, the Han River Valley was absorbed into Goguryeo in the mid-fifth century, and became Silla's territory in the year 553 (the 14th year of King Jinheung). Afterward, the current location of Gyeonggi-do, one of the nine states of Later Silla, was called Hansanju.

...
Wikipedia