The ridge, a karst, is not part of the Taygetus Massif, but, like the other mountains of Arcadia, is a nappe raised by the compressional forces on the Hellenic Plate by the subduction of Africa.

From the catchment at an altitude of 430 m (1,410 ft) part of the water flows into the Alpheios stream, which enters the upper Eurotas.

The classical Oineus was changed to Kelefina in the Middle Ages and not restored to its ancient name until recent times.

The old coastline can be approximated by a line on the periphery of the plain of Elos marking the border within which prehistoric archaeological sites are not found.

[citation needed] Mycenaean, or late Bronze Age Greece is known as Achaean Greek based on the Linear B and Hittite documents.

[citation needed] Beginning in 1968 the University of Cambridge began a survey by underwater archaeology of a drowned town between Pounta on the mainland and Elafonisos island on the eastern side of the Laconian Gulf.

The town extended over the entire drowned isthmus from 60 rock-cut tombs on the Pounta shore (a beach) to the remains of walls on Pavlopetri island off Elafonisos.

[12] The town was apparently continuously occupied from the late Neolithic to Byzantine times when it was drowned, perhaps by an earthquake.

The early Helladic pottery is "standard ... some showing close links with the Cyclades, western Crete and the northeastern Aegean."

This archaeological scenario is not incompatible with the Aegean distribution of the Leleges, although it is not possible to say who the early and middle Bronze Age inhabitants were.

In the 20th century a survey by the British School of Archaeology revealed that the entire ridge, located in the municipal unit of Therapnes, ancient Therapnē, had been covered by a walled Mycenaean town, dated to the late Bronze Age by the late Helladic (LH3) pottery[13] with some middle Helladic (MH) pottery in "pockets in the bedrock."

The archaeologists analyzing the site recognized a building Period I, dated between LH2B–LH3A1, the latter being brought to and end about 1425 BCE by a severe earthquake.

In Period II, dated to LH3A1, a villa-type structure was built of a terrace formed from previous building material further down to the south.

Period III, LH3A2–LH3B2, begins with 150 years of apparent abandonment and then a limited reconstruction of a one-story structure on the terrace.

Occupation of the hill went on through the Greek Dark Age, reduced to the Menelaon shrine in the Archaic and Classical Periods.

The shrine and its dedications identify it as the site of Homeric Sparta, capital of a ruling couple believed by the population of the Archaic Period to have been Menelaos and Helen.

The Spartans made little use of the left bank of the river: Only one permanent bridge has been found that crossed to it, at Therapne just south of the city.

[15] Modern Laconia is a political subdivision of Greece covering the Evrotas Valley, the massifs on either side, the two headlands, and the enclosed Laconian Gulf with its coastal islands.

However, the rich-soil plain is entirely divided into villages that practice agriculture, viticulture, and arboriculture intensely.

This is due to the interior's geographical location between Taygetus and Parnon mountains, completely cut out from the sea on all directions, some 30 km away from the shores.

[17] During July 2023 the Hydro Meteorological station of the National Observatory of Athens in Evrotas registered a record mean max temperature of 42.3°C.

[27] In modern times, much of the river water is used for irrigation, with the result that the Eurotas is almost dry during the summer months.

On 24 November 2005 heavy floods damaged buildings and stranded automobiles in the streets, and harmed orchards, including the valley's famous orange and olive groves.

The floods affected many villages along the valley as well as the town of Gytheio; 170 km2 (66 sq mi) of land was ruined.

Currently the nitrate waste from fertilizers is polluting the river, aggravated by diminished flow because of the irrigation demands on it.

[30] The Evrotas River occupies the floor of a rift valley, or graben, created by extensional forces acting over the Hellenic Plate in a northeast-southwest direction.

Under the entire valley is a deep aquifer in the limestone floor, containing water permeating downward through the horsts.