The Ogawa clan, said to be a branch of the Omi-Genji (a branch of the Minamotor clan descended from the Uda-Genji, and subsequently adopted into the Seiwa-Genji), was a local clan in Omi Province, serving as vassals to the Rokkaku clan in Minami Omi Province, and were the original lords of Sawayama-jo Castle.
小川氏は近江源氏の一派とみられる近江の土豪であり、南近江国の六角氏家臣、佐和山城主の出自である。