The line was built 1990–1996 and is an important east–west link connecting Gimpo Airport, the Yeouido business area, downtown Seoul, and the Gangdong residential districts.

In December 2010 the line is recorded as having the third highest WiFi data consumption in the Seoul Metropolitan area.

[3] The main branch of the line was extended to the city of Hanam with a total of 5 stations spanning 6.5 km.

[4][5] In January 2013, the Seoul Metropolitan Rapid Transit Corporation, which operated the line at the time, published free guidebooks features eight tours as well as recommendations for accommodations, restaurants and shopping centers.

[6] In the summer of 2013, the Seoul Metropolitan Rapid Transit Corporation to display water parks that are located near stations operated by the Seoul Metropolitan Rapid Transit Corporation on the LCD display screens both inside the train, and on the station platforms.