The Little Miami River (Shawnee: Cakimiyamithiipi) is a Class I tributary of the Ohio River that flows 111 miles (179 km) through five counties in southwestern Ohio in the United States. The Little Miami joins the Ohio River east of Cincinnati. It forms parts of the borders between Hamilton and Clermont counties and between Hamilton and Warren counties. The Little Miami River is one of 156 American rivers designated by the U.S.