Daegu, also known as Taegu, and officially the Daegu Metropolitan City, is the fourth largest city after Seoul, Busan, Incheon, and the third largest metropolitan area in South Korea. The 2005 census first found that Incheon's population was larger than Daegu's. with over 2.5 million people. The city is the capital and principal city of the surrounding province, Gyeongsangbuk-do, although it is not legally part of the province. These two areas are often called Daegu-Gyeongbuk, and have a combined population of over 5 million.

The city is located in south-eastern Korea about 80 km inside from seacoast, near the Geumho River and its mainstream, Nakdong River in Gyeongsang-do, also called the Yeongnam region. The Daegu basin, where the city lies, is the middle part and rare plain of that region. It made the city the region's center of politics, economy, and culture.

In ancient times, Daegu was part of the Silla Kingdom which unified the Korean Peninsula first, and in the Joseon Dynasty period, it was the capital of Gyeongsang-do which was one of eight provinces of the country. The city also was the home of the regimes in South Korea's rapid economic growth period (1960s–1980s). Today, the city has become one of the major cities of the country and is making efforts to be the center of the fashion and high-tech industries. Due to its status as a cultural center, there are many nicknames for the city including "Apple City", "Beauty City", "Textile City", "Fashion City"

Daegu has 9 sister cities.