Mobara is a city located in Chiba Prefecture. As of 1 December 2020, the city had an estimated population of 88,330 in 40,869 households and a population density of 880 persons per km2. The total area of the city is 99.92 square kilometres (38.58 sq mi)

The Bōsō Hill Range is a mountain range on the Bōsō Peninsula of Chiba Prefecture, Japan. The highest point in the Bōsō Mountain Range is at Mount Atago, with an altitude of 408.2 m (1,339 ft). The hill range runs from roughly in a line from Mobara or Ōamishirasato to Kisarazu, but is not formally defined. It is an important part of the Minami Bōsō Quasi-National Park.