During the early Meiji period, the village of Karumai within Kitakunohe District, Iwate Prefecture was created on April 1, 1889, with the establishment of the modern municipalities system.

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

Karumai, as part of Kunohe District, contributes two seats to the Iwate Prefectural legislature.

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

The economy of Karumai is based on agriculture, particularly the various grains, including millet, livestock raising, and the production of charcoal.