Alba County is a county (județ) of Romania located in the historic region of Transylvania. Its capital is Alba Iulia, a city with a population of 63,536.

Transylvania is a historical and cultural region in Central Europe, encompassing central Romania. To the east and south its natural border is the Carpathian Mountains and to the west the Apuseni Mountains. Broader definitions of Transylvania also include the western and northwestern Romanian regions of Crișana and Maramureș, and occasionally Banat. Historical Transylvania also includes small parts of neighbouring Western Moldavia and even a small part of south-western neighbouring Bukovina to its north east. The capital of the region is Cluj-Napoca.