The Mogami clan in Omori, Gamo County (present Omori-cho, Higashiomi City) was originally a distinguished clan in the Dewa Province and the lord of the Yamagata-jo Castle, but due to family issues, the amount of its chigyo-chi territory was reduced and transferred to this location.
蒲生郡大森（現・東近江市大森町）の最上氏は、出羽国の名族で山形城主であった最上氏が御家騒動により減知のうえ転封となった。