[2] Sumita is located in a basin in southeastern Iwate Prefecture in the southern Kitakami Mountains, surrounded by peaks with an elevation of between 600 and 1500 meters an all sides.

It was under the control of the Date clan during the Edo period, who ruled the Sendai Domain under the Tokugawa shogunate.

The villages of Kamiarisu, Shimoarisu and Setamai within Kesen District were created on April 1, 1889, with the establishment of the modern municipalities system.

Sumita has a mayor-council form of government with a directly elected mayor and a unicameral town council of 12 members.

In terms of national politics, the town is part of Iwate 2nd district of the lower house of the Diet of Japan.