Miyagi Prefecture was formerly part of the province of Mutsu. Mutsu Province, on northern Honshu, was one of the last provinces to be formed as land was taken from the indigenous Emishi, and became the largest as it expanded northward. The ancient capital was at Taga-jō in modern Miyagi Prefecture.
In the third month of the second year of the Wadō era (709), there was an uprising against governmental authority in Mutsu Province and in nearby Echigo Province. Troops were promptly dispatched to subdue the revolt.
In Wadō 5 (712), the land of Mutsu Province was administratively separated from Dewa Province. Empress Genmei's Daijō-kan continued to organize other cadastral changes in the provincial map of the Nara period, as in the following year when Mimasaka Province was divided from Bizen Province; Hyūga Province was sundered from Ōsumi Province; and Tanba Province was severed from Tango Province.
During the Sengoku period various clans ruled different parts of the province. The Uesugi clan had a castle town at Wakamatsu in the south, the Nanbu clan at Morioka in the north, and Date Masamune, a close ally of the Tokugawa, established Sendai, which is now the largest town of the Tōhoku region.
In the Meiji period, four new provinces were created from parts of Mutsu: Rikuchū, Rikuzen, Iwaki, and Iwashiro.
The area that is now Aomori Prefecture continued to be part of Mutsu until the abolition of the han system and the nationwide conversion to the prefectural structure of modern Japan.
Date Masamune built a castle at Sendai as his seat to rule Mutsu. In 1871, Sendai Prefecture was formed. It was renamed Miyagi prefecture the following year.
2011 Tōhoku earthquake and tsunami
On March 11, 2011, a 9.0 magnitude earthquake and a subsequent major tsunami hit Miyagi Prefecture, causing major damage to the area. The tsunami was estimated to be approximately 10 meters high in Miyagi Prefecture.
On April 7, 2011:
7.4-magnitude earthquake strikes off the coast of Miyagi, Japan, Japan's meteorological agency says. Workers were then evacuated from the nearby troubled Fukushima-Daiichi nuclear facility once again, as a tsunami warning was issued for the coastline. Residents were told to flee for inner land at this time.
Officials from the U.S. Geological Survey later downgraded the magnitude to 7.1 from 7.4.
In 2013, Crown Prince Naruhito and Crown Princess Masako visited the prefecture to see the progress made since the tsunami.