下野国
After the formation of the Tokugawa Shogunate, Ōta Sukemune served as a "hatamoto" to Tokugawa Ieyasu after the fall of the Later Hōjō clan, becoming one of the first "wakadoshiyori". His sister also became a concubine of Tokugawa Ieyasu. In 1635 he was elevated to the ranks of "daimyō" with revenues of 15,600 "koku" in Yamakawa Domain in Shimotsuke Province. He relocated to Nishio Domain in Mikawa Province with an increase to 35,000 "koku", and then to the more prestigious Hamamatsu Domain (35,000 "koku") in Tōtōmi Province.