An ancient province located in south-central Japan, now the western part of Shizuoka prefecture. Tootoumi was controlled by the Imagawa Clan during the Sengoku Period; when Imagawa Yoshimoto fell to Oda Nobunaga, Takeda Shingen and Tokugawa Ieyasu both invaded it and partitioned it between them. During the Edo Period, Hamamatsu-han and Kakegawa-han were established in Tootoumi, ruled by a hereditary vassal of the Tokugawa Clan.