WEBŌnojō (大野城市, Ōnojō-shi) is an area located in Fukuoka Prefecture, Japan. Its name is made up of the kanji for 'big', 'field', and 'castle'. As of 31 March 2024, the city had an estimated population of 102,818 in 46689 households, and a population density of 3800 persons per km 2.