Cașin (Râul Negru)
The Cașin is a right tributary of the river Râul Negru in Romania. It discharges into the Râul Negru in Catalina. It flows through the villages and towns Plăieșii de Sus, Plăieșii de Jos, Iacobeni, Valea Seacă, Sânzieni, Târgu Secuiesc and Catalina. Its length is and its basin size is.Tributaries
The following rivers are tributaries to the river Cașin :