Zemplín is the name of an informal traditional region located in eastern Slovakia.
Zemplín region stretches from the Carpathian Mountains in the north to the lowest point in Slovakia at 94 meters (308 ft) AMSL.
Administratively, the region is divided between Košice Region, which includes Trebišov and the western part of Michalovce District (if Ung county is included, eastern part of Michalovce and whole Sobrance District also belong to Zemplín), and Prešov Region, fully including Humenné, Snina and Medzilaborce districts and from bigger part including Vranov nad Topľou and Stropkov districts.
The southern half (including the bigger part of the divided Sátoraljaújhely) stayed in Hungary as the county Zemplén.
During World War II, when Czechoslovakia was split temporarily, some of the Czechoslovak part of Zemplen county was occupied by Hungary under the First Vienna Award, and added to the counties Zemplén and Ung.