The Sendai Domain owes its existence to Date Masamune, the warlord known as the One-Eyed Dragon for losing his right eye to smallpox as a child. In the closing years of the sixteenth century, Masamune presented himself to Toyotomi Hideyoshi during the Odawara Campaign and received new lands, the former fiefs of the Kasai and Osaki families, in exchange for surrendering his hereditary territories of Yonezawa, Aizu, and Sendo. It was a calculated trade. Masamune first took up residence at Iwadeyama Castle, then began construction of a far grander seat of power: Sendai Castle, perched on the wooded heights of Mount Aoba. From that hilltop fortress, which he started building in December 1600 after the Battle of Sekigahara, the Date clan would govern the largest contiguous domain in northern Japan for the next two and a half centuries.

Under the kokudaka system, which rated a domain's wealth by its rice production, Sendai was assessed at 625,000 koku, making it the third-richest domain in all of Japan after Satsuma and Kaga. Its territory was enormous: nearly all of present-day Miyagi Prefecture, parts of southern Iwate Prefecture, and a slice of northeastern Fukushima Prefecture. The Date lords were classified as tozama daimyo, meaning they were "outside lords" who had not been hereditary vassals of the Tokugawa before the great unification. This status kept them at arm's length from the Shogun's inner circle but granted them a degree of autonomy that few other lords enjoyed. They minted their own coins, ran their own school, the Yokendo, and maintained a fighting force organized into ten units of 360 men each, a standing army of 3,600 warriors backed by layers of retainers ranked across eleven distinct tiers.

The social architecture of the Sendai Domain was intricate even by Edo-period standards. At the top sat the Ichimon, blood relatives of the Date clan who held prestige but no administrative power. Below them, the Ikka families handled the high-level daily governance of the domain. Further down the hierarchy stretched nine additional ranks, from the Shukuro hereditary magistrates to the Sotsu foot soldiers and laborers at the bottom. Some higher-ranked retainers accumulated enough land and influence to establish their own subdomains. Mizusawa Domain was one short-lived example; the Ichinoseki Domain, ruled by the Tamura family, survived all the way to the end of the Edo period. Even the rituals of rank were precise: certain retainers earned the right to present the lord with a sword at New Year's celebrations and receive a cup of sake in return, a ceremonial exchange that marked their station as surely as any title.

When the Boshin War erupted in 1868, Sendai initially tried diplomacy. The domain's lord, Date Yoshikuni, accepted imperial envoys and provided cooperation to the new Meiji government while arguing against the punitive treatment of neighboring Aizu. He protested that the campaign against Aizu was like "a sentence being passed on one who never had a trial." For months, Sendai walked a tightrope between compliance and conscience. The discovery of Sera Shuzo's letter snapped that balance. Outraged that their cooperation had counted for nothing, Sendai samurai killed Sera and threw the domain's weight behind the Ouetsu Reppan Domei, a coalition of northern domains that fought the imperial army through the summer and fall of 1868. The coalition ultimately failed. Sendai was punished, its holdings reduced, and Shiroishi Castle was stripped away and given to the Nanbu clan. In 1871, when the Meiji government abolished the feudal domain system entirely, the Sendai Domain ceased to exist.