The Târnava Mare River ("Big Târnava"; Nagy-Küküllő; Große Kokel) is a river in Romania. Its source is in the Eastern Carpathian Mountains, near the sources of the Mureş and Olt in Harghita County. It flows through the Romanian counties of Harghita, Mureş, Sibiu, and Alba. The cities of Odorheiu Secuiesc, Sighişoara, and Mediaş lie on the Târnava Mare. It joins the Târnava Mică River in Blaj, forming the Târnava.