The Târnava Mare is a river in Romania. Its total length is 223 km, and its drainage basin area is 3,666 km2. Its source is in the Eastern Carpathian Mountains, near the sources of the Mureș and Olt in Harghita County. It flows through the Romanian counties of Harghita, Mureș, Sibiu, and Alba. The cities of Odorheiu Secuiesc, Sighișoara, and Mediaș lie on the Târnava Mare. It joins the Târnava Mică in Blaj, forming the Târnava.