Rio-Antirrio bridge in the context of "Cable-stayed bridge"

The Gulf of Patras (Greek: Πατραϊκός Κόλπος, Patraikós Kólpos) is a branch of the Ionian Sea in Western Greece. On the east, it is closed by the Strait of Rion between capes Rio and Antirrio, near the Rio-Antirrio bridge, that is the entrance of the Gulf of Corinth. On the west, it is bounded by a line from Oxeia island to Cape Araxos. To the north it is bounded by the shore of Aetolia-Acarnania in continental Greece, and to the south by Achaea in the Peloponnese peninsula. It is 40–50 km (25–31 mi) long, 10–20 km (6–12 mi) wide, and has an area of 350–400 km.

The port city of Patras lies to the southeast and is the only major port on the gulf. It serves ferries to Ancona and Brindisi in Italy and to Cephalonia. On the northern shore Missolonghi, also has a port. The old ports of Rio and Antirrio lie at the east end of the Gulf; there is a ferry service between them which complements the traffic over the Rio-Antirio bridge. The gulf is rich in fish and molluscs, including sea snails and clams.

National Road 5 (Greek: Εθνική Οδός 5, abbreviated as EO5) is a single carriageway road in western Greece. It connects Antirrio, at the north end of the Rio-Antirrio bridge, with Ioannina in northwestern Greece, passing through Agrinio and Arta. The southern part, between Amfilochia and Antirrio, is part of the European route E55. The northern part, between Ioannina and Amfilochia, forms the European route E951. It passes on the east side of the Ambracian Gulf. In the future much of the traffic that used this road will be diverted to the new A5 motorway (Ionia Odos) motorway, which has already taken over parts of the road. Νear Arta there is a 200m. tunnel (Kleisoura tunnel) which opened in 1969