The Gulf of Corinth or the Corinthian Gulf (Κορινθιακός Kόλπος, Korinthiakόs Kόlpos, in Greek) is a deep inlet of the Ionian Sea separating the Peloponnese from western mainland Greece. It is bounded in the east by the Isthmus of Corinth which includes the shipping-designed Corinth Canal and in the west by the Strait of Rion which widens into the shorter Gulf of Patras (part of the Ionion Sea) and of which the narrowest point is crossed since 2004 by the Rio-Antirio bridge. The Gulf is bordered by the large administrative divisions (prefectures): Aetolia-Acarnania and Phocis in the north, Boeotia in the northeast, Attica in the east, Corinthia in the southeast and south and Achaea in the southwest.