The Argolis Gulf was the center of prehistoric civilization in Greece, as in the developed coastline of some of the most important societies of prehistoric Greece, as the prehistoric town of Lerna and the prehistoric cave Franchthi society. Nearby are Mycenae, the most important city before the 7th century B.C., Argos, Tiryns with Cyclopean Walls, Assini and Epidavros, holy place of Ancient Greece with the Asklepeion and the famous theatre.
The Argolis Gulf is located between Argolis Peninsula and the east coast of Arcadia and Laconia im Peloponissos. It is the easternmost of the three large bays formed the coastline of the southern Peloponnese. Along with the Saronic Gulf and the southern coast of Argolis defines the area of the Argosaronic Gulf
The coast of Argolis is steep in the southern part of Argolis and Arcadia and smoothly on the north side, which meets the plain of Argos. The major cities and towns on the coast of Argolic Gulf is Nafplion, Astros, Tyros, Tolo, Porto Heli, Leonidio and Nea Kios. Inside the bay of Argolis are several islets. The largest of these are Psili, Plateia and Romvi, all three are situated on the coast of Argolis. At the exit of the Argolid Gulf are Spetses.
(Translation from Wikipedia, with some add-on by C. Theodorou)