In classical and late antiquity, Illyria (/ɪˈlɪəriə/; Ancient Greek: Ἰλλυρία, Illyría or Ἰλλυρίς, Illyrís; Latin: Illyria, Illyricum) was a region in the western part of the Balkan Peninsula inhabited by numerous tribes of people collectively known as the Illyrians.
The Ancient Greeks initially used the term Illyris to define approximately the area of northern and central Albania down to the Aoös valley (modern Vjosa) and the Bay of Vlorë, including in most periods much of the lakeland area (Ohrid and Prespa). It corresponded to the region that neighboured Macedonia and Epirus. In Roman times the terms Illyria, Illyris, or Illyricum were extended from the territory that was roughly located in the area of the south-eastern Adriatic coast (modern Albania and Montenegro) and its hinterland, to a broader region stretching between the whole eastern Adriatic and the Danube.