Messantia is on the coast of Argos. It's one of the major seaports of the Conan world.
Messantia:---capital of Argos and one of the greatest seaports of the Hyborian Age. Messantia was the terminus for the Road of Kings and for trade routes out of Aquilonia, Koth, Shem, Zingara, and the interior. The main road from Tarantia went along the eastern border of Poitain, coming into the Argossean uplands and winding to the coast. A shorter but more dangerous route from Poitain followed the Zingaran shore of the Alimane, then ran southeast through a ghoul-haunted forest. Messantia was on the estuary of the Khorotas and is presumed to be not far from Venzia. (Pool of the Black One, Conan the Buccaneer, Treasure of Tranicos, Hour of the Dragon, Conan of the Isles, Conan the Guardian, et al.)
Messantia -- the capital city of Argos. Lying at the mouth of the Khorotas River, Messantia is a major seaport and shipyard for ships from Zingara to Stygia. Although Messantia has many of the same problems as any seaport town, by 1310, when King Ariostro sat upon the Argossean throne, Messantia had become "so safe a juicy wench can walk the length of the waterfront unmolested".