It links the cities of Ioannina and Kozani via Konitsa and Siatista.

[1] It passes through the Ioannina, Kastoria and the Kozani regional units.

[2] Since the opening of the A2 motorway (Egnatia Odos), it is no longer the fastest connection between Kozani and Ioannina.

The section between Ioannina and Kalpaki is part of the European route E853.

The EO20 is officially defined as a route through the Pindus mountain range and around the northwestern boundaries of Pindus National Park: it runs between Kozani to the east and Ioannina to the west, via Bara (Siatista), Neapoli, Tsotyli, Pentalofos, Eptachori [el], Konitsa and Kalpaki.