Chungju, city, North Chungcheong do (province), central South Korea. Connected with Seoul by water transport on the Han River, it was the administrative and economic center of the province until the provincial government was removed to Cheongju in 1909. Although traditionally an agricultural center, the city began to develop industrially in the 1950s with the construction of a fertilizer plant. Mount Worak (Woraksan) National Park is southeast of the city. Pop. (2020) 218,412.