Chugoku is located in the most western part of the main island "Honshu". The south part of Chugoku faces toward the Seto Inland Sea and the north part of Chugoku faces toward the Sea of Japan. Chugoku Mountains divide Chugoku into the "Sanyo" side and the "Sanin" side.

Chugoku has five prefectures. They are Okayama, Hiroshima, Tottori, Shimane and Yamaguchi. Okayama and Hiroshima are on the Sanyo side. Tottori and Shimane are on the Sanin side. Yamaguchi is on the west end of Honshu, facing both the Seto Inland Sea and the Sea of Japan. Sanyo is also an industrial area and the Sanyo Shinkansen runs through Okayama, Hiroshima and Yamaguchi. On the other hand, Sanin has less industrial output.