Argos is a nation of paramount seafarers, with cosmopolitan cities along the coast. Its capital, Messantia, lay on the coast at the estuary of the Khorotas River. The most fertile region in Argos is the Khorotas River valley. The valley is filled with fruit orchards, farms, and oak forests where Argos' shipbuilding industry gets its wood.
The inland provinces were culturally rather backward. Along the Zingaran border were ghoul-haunted forests; south of these lay orchards and croplands.
The Argossean people are an amalgam of Zingaran and Shemite races. They are the best sailors in the Hyborian world -- according to everyone but the mariners of Zingara!
Argos was anciently a part of Acheron. It may have been the third of the Hyborian kingdoms to be established, after Nemedia and Aquilonia. Argos has a long-standing feud with Zingara, based on their maritime rivalry. Zingara essayed an incursion into Argos in the recent past. The Argosseans under King Milo trounced King Ferdrugo's invaders soundly.
References: Hyborian Age I-II, City of Skulls, Queen of the Black Coast, Snout in the Dark, Castle of Terror, Conan the Buccaneer, Red Nails, Hawks Over Shem, Treasure of Tranicos, Hour of the Dragon, Conan the Liberator, Conan the Guardian, et al.