WEBShimonoseki ( Japanese: 下関市, Hepburn: Shimonoseki-shi) is a city located in Yamaguchi Prefecture, Japan. As of 30 June 2023, the city had an estimated population of 248,193 in 128762 households and a population density of 350 persons per km 2. [1] . The total area of the city is 716.18 square kilometres (276.52 sq mi).