The area of present-day Shiwa was part of ancient Mutsu Province, and has been settled since at least the Jōmon period.

During the Meiji period, this exclave became the village of Shiwa, and the town of Hizume and the villages of Furudate, Mizuwake, Akaishi, Hikobe, Sahinai, Akasawa, ane Nagaoka were established within Shiwa District on April 1, 1889 with the establishment of the modern municipalities system.

Shiwa has a mayor-council form of government with a directly elected mayor and a unicameral city legislature of 18 members.

In terms of national politics, the city is part of Iwate 1st district of the lower house of the Diet of Japan.

The local economy of Shiwa is traditionally based on agriculture, primarily rice cultivation, apples, grapes and cucumbers; however, due to its proximity to Morioka city, it is increasingly serving as a bedroom community.