The Kantō region (関東地方, Kantō-chihō) is a geographical area of Honshū, the largest island of Japan. The region encompasses seven prefectures which overlaps the Greater Tokyo Area: Gunma, Tochigi, Ibaraki, Saitama, Tokyo, Chiba, and Kanagawa. Within its boundaries, slightly more than 40 percent of the land area is the Kantō plain. The rest consists of the hills and mountains that form the land borders.