Somogy county lies in south-western Hungary, on the border with Croatia. It stretches between the river Drave and the southern shore of Lake Balaton. It shares borders with the Hungarian counties Zala, Veszprém, Fejér, Tolna and Baranya. It is the most sparsely populated county in Hungary. The capital of Somogy county is Kaposvár. Its area is 6036 km².

Somogy was also the name of a historic administrative county (comitatus) of the Kingdom of Hungary. Its territory, which was slightly larger than that of present Somogy county, is presently in south-western Hungary. The capital of the county was Kaposvár.