Borsod-Abaúj-Zemplén is an administrative county in north-eastern Hungary (commonly called "Northern Hungary"), on the border with Slovakia (Košice Region). It shares borders with the Hungarian counties Nógrád, Heves, Hajdú-Bihar and Szabolcs-Szatmár-Bereg. The capital of the county is Miskolc.
It is the second largest county of Hungary both by area (after Bács-Kiskun) and by population (after Pest County). It is the only Hungarian county with two UNESCO World Heritage Sites (the Caves of Aggtelek Karst and Slovak Karst and the Tokaj Wine Region Historic Cultural Landscape).