It was located in the regional unit of Achaea, northern Peloponnesos, two kilometres (12 stadia) from the Corinthian Gulf and near the city of Boura, which, like Helike, was a member of the Achaean League.

Several events were construed in retrospect as having warned of the disaster: some "immense columns of flame" appeared, and five days previously, all animals and vermin fled the city, going toward Keryneia.

[11] About 150 years after the disaster, the philosopher Eratosthenes visited the site and reported that a standing bronze statue of Poseidon was submerged in a "poros", "holding in one hand a hippocamp", where it posed a hazard to those who fished with nets.

[12] The meaning of poros in ancient Greek is not fully clear, but could refer to an inland lagoon, lake, or narrow strait.

Most archaeologists thought it referred to the Gulf of Corinth, but there was disagreement from Professor Dora Katsonopoulou: For the sea was raised by an earthquake and it submerged Helice, and also the temple of the Heliconian Poseidon, whom the Ionians worship even to this day, offering there the Pan-Ionian sacrifices.

And Eratosthenes says that he himself saw the place, and that the ferrymen say that there was a bronze Poseidon in the strait, standing erect, holding a hippo-campus in his hand, which was perilous for those who fished with nets.

And Heracleides says that the submersion took place by night in his time, and, although the city was twelve stadia distant from the sea, this whole district together with the city was hidden from sight; and two thousand men who had been sent by the Achaeans were unable to recover the dead bodies; and they divided the territory of Helice among the neighbors; and the submersion was the result of the anger of Poseidon, for the lonians who had been driven out of Helice sent men to ask the inhabitants of Helice particularly for the statue of Poseidon, or, if not that, for the model of the temple; and when the inhabitants refused to give either, the Ionians sent word to the general council of the Achaeans; but although the assembly voted favorably, yet even so the inhabitants of Helice refused to obey; and the submersion resulted the following winter; but the Achaeans later gave the model of the temple to the lonians.Around 174 AD, the traveler Pausanias visited a coastal site still called Helike, located seven kilometres southeast of Aigio, and reported that the walls of the ancient city were still visible underwater, "but not so plainly now as they were once, because they are corroded by the salt water".

Adalberto Giovannini [de] argued that the submergence of Helike might have inspired Plato to end his story about Atlantis with its submersion.

[14] Ancient scholars and writers who visited the ruins include the Greeks Strabo,[15] Pausanias and Diodoros of Sicily,[16] and the Romans Aelian[8] and Ovid.

The aftershock was said to have lasted a minute and a half, during which the sea rose at the mouth of the Selinous River and extended to cover all the ground immediately below Aigio (the ancient Αἴγιον).

People were divided in their opinions about the exact location of Helike and produced numerous works and hypotheses: In 1826, French diplomat and archaeologist François Pouqueville, who wrote the Voyage en Grèce;[19] in 1851 Ernst Curtius the German archaeologist and historian who speculated about its location;[20] in 1879 J. F. Julius Schmidt, the director of Athens Observatory, issuing a study comparing the Aegeion earthquake which occurred 26 December 1861 with an earthquake which might have destroyed Helike;[21] in 1883 Spiros Panagiotopoulos, the mayor of Aegeion city, wrote about the ancient city; in 1912 the Greek writer P. K. Ksinopoulos wrote The City of Aegeion Through the Centuries[22] and in 1939 Stanley Casson, an English art scholar and army officer who studied classical archaeology and served in Greece as liaison officer, addressed the problem.

Also, if an earthquake caused the sections of coastline to fall into the sea, this would have created a tsunami, which in turn would have flooded the inland lagoon with the city in it.

Over time, the river sediment coming down from the mountains would have filled in the lagoon hiding the city remains beneath the solid ground.

[32] Further confirming that the discovered site belongs to Helike, the earthquake destruction layer consisting of cobblestones, clay roof tiles, and pottery was uncovered in 2012.