Anigros was a Potamoi of a small stream in Elis which is part of Peloponnessos which is located in Southern Greece. While Anigros was in the south near Alpheios (a major river which was a bit north, Anigros was not a tributary of it or any other river. Anigros flowed from Mount Lapithos and Minthe emptying out into the Ionian Sea after it passed through Elis.
It is at the mountains where Anigros' domain begins that there is a cave in which dwell the Anigrides nymphs (daughters of Anigros). These nymphs call themselves that because close by there is a spring. It is possible that the region is muddy and marshy because of that spring but it is also possible that it is muddy because certain Kentauroi supposedly washed off poison that they got from the Hydra. Yet another theory exists that the region is muddy and swampy because many would bathe in the area because the river supposedly provided a cure for leprosy, scabies and even elephantiasis. It is remarkable that a stream could provide so much help.
"At the base of these mountains, on the seaboard, are two caves. One is the cave of the nymphs called Anigriades; the other is the scene of the stories of the daughters of Atlas and of the birth of Dardanus. And here, too, are the sacred precincts called the Ionaeum and the Eurycydeium. Samicum is now only a fortress, though formerly there was also a city which was called Samus, perhaps because of its lofty situation; for they used to call lofty places "Samoi." And perhaps Samicum was the acropolis of Arene, which the poet mentions in the Catalogue: “"And those who dwelt in Pylus and lovely Arene." ”For while they cannot with certainty discover Arene anywhere, they prefer to conjecture that this is its site; and the neighboring River Anigrus, formerly called Minyeius, gives no slight indication of the truth of the conjecture, for the poet says: “"And there is a River Minyeius which falls into the sea near Arene."
”(Hom. Il. 11.722) For near the cave of the nymphs called Anigriades is a spring which makes the region that lies below it swampy and marshy. The greater part of the water is received by the Anigrus, a river so deep and so sluggish that it forms a marsh; and since the region is muddy, it emits an offensive odor for a distance of twenty stadia, and makes the fish unfit to eat. In the mythical accounts, however, this is attributed by some writers to the fact that certain of the Centaurs here washed off the poison they got from the Hydra, and by others to the fact that Melampus used these cleansing waters for the purification of the Proetides. The bathing-water from here cures leprosy, elephantiasis, and scabies. It is said, also, that the Alpheius was so named from its being a cure for leprosy."
- Strabo, Geography 8. 3. 19 Greek Geographer C1st B.C. to C1st A.D."