Onjuku is a town located in Chiba, Japan. As of 30 November 2018, the town had an estimated population of 7,523 in 3683 households and a population density of 300 persons per km2. The total area o the town is 24.86 square kilometres. The name of the town is made of two kanji characters: the first 御 meaning "honorable", and the second 宿 meaning "residence".