Archaeologically, the Isthmus is rich in ancient remains, including temples, sanctuaries, and evidence of the Isthmian Games, showcasing its importance as a center of culture, commerce, and religious activity in antiquity.

The Isthmus of Corinth, a pivotal geographical feature of Greece, has long been a site of historical and archaeological significance. Known for its strategic location, it served as a critical link between the Peloponnese and the rest of the Greek mainland, facilitating trade, cultural exchange, and military endeavors throughout antiquity. The ancient city of Corinth flourished in this area, renowned for its wealth and influence, as well as its renowned sanctuaries, particularly the Sanctuary of Poseidon at Isthmia. Excavations in the region have unveiled a rich tapestry of human activity, from the prehistoric era through the Roman period, highlighting the isthmus's role as a hub of social, economic, and religious life in the ancient world. As researchers continue to explore its archaeological sites, the Isthmus of Corinth remains a focal point for understanding the complexities of ancient Greek civilization.

circa 600 BCE

Diolkos
The Diolkos was a paved trackway near Corinth in Ancient Greece which enabled boats to be moved overland across the Isthmus of Corinth. The shortcut allowed ancient vessels to avoid the long and dangerous circumnavigation of the Peloponnese peninsula. The main function of the Diolkos was the transfer of goods, although in times of war it also became a preferred means of speeding up naval campaigns. The 6 to 8.5 kilometre long roadway was a rudimentary form of railway, and operated from circa 600 BCE until the middle of the first century CE. The Diolkos combined the two principles of the railway and the overland transport of ships, on a scale that remained unique in antiquity.

circa 470 BCE - 396 CE

Temple of Poseidon
The Sanctuary of Poseidon, also known as the Isthmia Sanctuary, was an ancient Greek religious complex on the Isthmus of Corinth. Isthmia sanctuary was located on the key land route connecting Athens and central Greece with Korinthos and the Peloponnese. Its location on the Isthmus, between the major Corinthian ports of Lechaeum on the Gulf of Corinth and Cenchreae on the Saronic Gulf, made Isthmia a natural site for the worship of Poseidon, god of the sea and also of mariners.

circa 408-450 CE

Hexamilion Wall
The Hexamilion wall (literally meaning the six-mile long wall) was a defensive fortification built across the Isthmus of Korinthos, from the Saronic to the Corinthian Gulf. It was constructured in the early years (between 408 and 450 CE) of the fifth century CE, to protect the Peloponnese against the barbarian attacks coming from the north. The Hexamilion wall was an enormous engineering and military undertaking. It is almost eight kilometers long, three meters wise and 7-8 meters high, with more than 100 towers along its length. The fortification ran along a ridge on the northern edge of the Sanctuary of Poseidon, frequently making use of the foundations of ancient structures and buildings as an aid in its construction. A large fortress was built in the vicinity of the sanctuary, and blocks from many of the buildings in the sanctuary were removed from the collapsed buildings (including the Temple of Poseidon and the Roman baths) and used in the fortifications. The Hexamilion wall was rebuilt several times, most notable by the emperors Justinian (circa 527-565 CE) and Manuel II Palaiologos (circa 1415 CE). After the fall of Constantinople in 1453 CE, the Venetians made several attemts to rebuild the walls and use them as a means to defend the Peloponnese against the Ottoman Turks, but these efforst ultimately came to nothing as the Venetian state did not have the financial resources to effectively complete the rebuilding task.

The fortifications served practical needs of defense and they also figured in myths and stories that represented the hopes and aspirations of the Greek people during the Byzantine and later periods. A settlement of considerable size grew up within and around the fortification during the Middle Ages, and this continued to exist apparently until the final abandonment of the Hexamilion wall in 1715 CE.