- Gongju is located in the center of South Korea and of Chungcheongnam-do (South) Province.
- It is sharing borders with 7 cities and counties in Chungcheongnam-do (South) Province - Yeongi County and Daejeon Metropolitan City in the east, Cheongyang County and Yesan County in the west, Buyeo County and Nonsan City in the south and Asan City and Cheonan City in the north.
- Two major mountains are located near Gongju (Mt. Charyong and Mt. Gyeryong), and Geum River runs through the city from east to west. Several tributary rivers such as Yugu-cheon, Jeongan-cheon, Daekyocheon, Jemin-cheon, and Hyoljeo-cheon meet here.
- Gongju has one nationally-managed river (Geum River) and one locally-managed river (Yugu-cheon). The combined length of these rivers reach 1,159km.
- Mt. Charyong blocks the freezing north wind, making Gongju warmer than northern cities, But affected by Geum River, the city shows the continental temperature pattern with a wide range of temperature between the hottest and coldest periods of the year.