Chungju (chōngˈjōˈ) [key], city (1995 pop. 205,131), North Chungcheong prov., central South Korea. Chungju is an important agricultural center with a large fertilizer plant; it also is a significant producer of caviar from farm-raised sturgeon. The city is linked to Seoul, to the northwest, by the Han River. The Chungju Lake reservoir to the east is a recreation area.