Dongjak District (Dongjak-gu) is one of the 25 gu that make up the city of Seoul, South Korea. Its name was derived from the Dongjaegi Naruteo Ferry, on the Han River which borders the district to the north. It was the 17th gu created in Seoul, after being separated from Gwanak District on 1 April 1980.

The Seoul Capital Area or Gyeonggi region, is the metropolitan area of Seoul, Incheon, and Gyeonggi Province, located in north-west South Korea. Its population of 26 million is ranked as the fourth largest metropolitan area in the world. Its area is about 12,685 km2 (4,898 sq mi). It forms the cultural, commercial, financial, industrial, and residential center of South Korea. The largest city is Seoul, with a population of approximately 10 million people, followed by Incheon, with 3 million inhabitants.