The city is located in the center of South Korea. It is an important place where traffic diverges into two major expressways, the Gyungbu Expressway going to the east and the Honam Expressway to the west. It has become the hub of national traffic both in name and reality, after the rapid transit railway system started operation in April, 2004.

Daejeon is the fifth largest city among South Korea's top six cities, including Seoul, Busan, Daegu, Incheon, and Gwangju. Its population is approximately 1,500,000 and it covers an area of 539.83 km² at the end of 2007.

Daejeon is called the city of science because there are more than 200 research and development institutions in Daejeon. Daejeon once hosted EXPO 93 at EXPO SCIENCE PARK just next to DCC, the venue. Daejeon with its great heritage has grown into a world-class science city.