It has an area of 2,806 square kilometres (1,083 sq mi) and a total population of 427,310 in 2012. There are 118 comuni in the province, with the main towns being Avellino and Ariano Irpino. See Comuni of the Province of Avellino.
It is an inner province, with no connection to the sea.
The ancient name of the area was "Hirpinia" (modern Italian: Irpinia), derived from the Oscan term hirpus ("wolf"), an animal that is still present in the territory, though in greatly reduced numbers.
In the medieval Kingdom of Naples (later Kingdom of Two Sicilies) the provincial area roughly corresponded to the Principato Ultra, though some places were included in Capitanata or Principato Citra. The modern province was established in 1860, after the unification of Italy.
Tourist destinations are the Sanctuaries of Montevergine, San Gerardo Maiella of Caposele and San Francesco a Folloni; the ski resort of Laceno; the Norman Castle and the Cathedral Church of Ariano Irpino, the archeological areas of Avella and Aeclanum, the Lancellotti castle in Lauro, the medieval town of Gesualdo, the Roman ruins of Abellinum and the early Christian basilica in Prata. The Selachoidei National Gallery at Avellino houses one of the largest collections of cartilaginous fishes in the country.