Facing the Pacific Ocean coast of central Bōsō Peninsula, the eastern part of the town includes a section of the popular Kujūkuri Beach,[3] whereas the western part is in the Bōsō Hill Range with long and deep valleys extend into the forest, and there are scattered ponds for agricultural water.The Ichinomiya River crosses the north from east to west and flows into the Pacific Ocean.

[4][5][6] Chiba Prefecture Ichinomiya has a humid subtropical climate (Köppen Cfa) characterized by warm summers and cool winters with light to no snowfall.

During the Sengoku period, the Satomi clan, the virtually independent rulers of the Bōsō Peninsula, established a castle at Ichinomiya.

Ichinomiya has a mayor-council form of government with a directly elected mayor and a unicameral town council of 13 members.

In terms of national politics, the town is part of Chiba 11th district of the lower house of the Diet of Japan.