Abaúj is a historic administrative county (comitatus) of the Kingdom of Hungary. In parts of the 19th century, and in the beginning of the 20th century, it was united with Torna County to form Abaúj-Torna county. Its territory is now in eastern Slovakia and north-eastern Hungary. Today Abaúj and Abov are only informal designations of the corresponding territories in Hungary and Slovakia.