The Corinth Canal is a canal

Canal

Canals are man-made channels for water. There are two types of canal:#Waterways: navigable transportation canals used for carrying ships and boats shipping goods and conveying people, further subdivided into two kinds:...

 that connects the Gulf of Corinth

Gulf of Corinth

The Gulf of Corinth or the Corinthian Gulf is a deep inlet of the Ionian Sea separating the Peloponnese from western mainland Greece...

 with the Saronic Gulf

Saronic Gulf

The Saronic Gulf or Gulf of Aegina in Greece forms part of the Aegean Sea and defines the eastern side of the isthmus of Corinth. It is the eastern terminus of the Corinth Canal, which cuts across the isthmus.-Geography:The gulf includes the islands of; Aegina, Salamis, and Poros along with...

 in the Aegean Sea

Aegean Sea

The Aegean Sea[p] is an elongated embayment of the Mediterranean Sea located between the southern Balkan and Anatolian peninsulas, i.e., between the mainlands of Greece and Turkey. In the north, it is connected to the Marmara Sea and Black Sea by the Dardanelles and Bosporus...

. It cuts through the narrow Isthmus of Corinth

Isthmus of Corinth

The Isthmus of Corinth is the narrow land bridge which connects the Peloponnese peninsula with the rest of the mainland of Greece, near the city of Corinth. The word "isthmus" comes from the Ancient Greek word for "neck" and refers to the narrowness of the land. The Isthmus was known in the ancient...

 and separates the Peloponnesian peninsula from the Greek

Greece

Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....

 mainland, thus effectively making the former an island

Island

An island or isle is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, cays or keys. An island in a river or lake may be called an eyot , or holm...

. The builders dug the canal through the Isthmus at sea level

Sea level

Mean sea level is a measure of the average height of the ocean's surface ; used as a standard in reckoning land elevation...

; no locks are employed. It is 6.4 kilometres (4 mi) in length and only 21.3 metres (69.9 ft) wide at its base, making it unpassable for most modern ships.