The Rioni (Georgian: რიონი, Rioni; Ancient Greek: Φᾶσις, Phᾶsis) is the main river of western Georgia. It originates in the Caucasus Mountains, in the region of Racha and flows west to the Black Sea, entering it north of the city of Poti (near ancient Phasis). The city of Kutaisi, once the ancient city of Colchis, lies on its banks. It drains the western Transcaucasus into the Black Sea while its sister, the Kura, drains the eastern Transcaucasus into the Caspian Sea.

Rioni river - Georgia (Europe).jpg
Rioni River in Racha Region
Rioni is located in Georgia
Native nameრიონი  (Georgian)
Physical characteristics
SourceMain Caucasian Range
Caucasus Mountains
MouthBlack Sea
 • location
 • coordinates
42°11′3″N 41°38′10″E / 42.18417°N 41.63611°E / 42.18417; 41.63611Coordinates: 42°11′3″N 41°38′10″E / 42.18417°N 41.63611°E / 42.18417; 41.63611
Length327 km (203 mi)
Basin features
 • leftTekhuri, Qvirila
 • rightTskhenistsqali


Herodotus considered the Rioni river as a boundary between Europe and Asia[1]

Ancient authorsEdit

Known to the ancient Greeks as the Phasis River, Rioni was first mentioned by Hesiod in his Theogony (l.340); Plato has Socrates remark: "I believe that the earth is very large and that we who dwell between the pillars of Hercules and the river Phasis live in a small part of it about the sea, like ants or frogs about a pond" (Phaedo, 109a). Later writers like Apollonius Rhodius (Argonautica 2.12.61), Virgil (Georgics 4.367) and Aelius Aristides (Ad Romam 82) considered it the easternmost limit of the navigable seas. Socrates in Phaedo 109a referred to the portion of the world he knew of as between the Pillars of Hercules and the River Phasis, while Herodotus and Anaximander considered Rioni a boundary between Europe and Asia.[1] The famed voyage of Jason and the Argonauts, though semi-mythological, was said to have occurred by the Argonauts sailing up the Rioni River from its mouth at the Black Sea at Poti, to Kutaisi, Georgia.[citation needed]


The term "pheasant" and the scientific name Phasianus colchicus are derived from "Phasis" and "Colchis", as this was said to be the region from which the common pheasant was introduced to Europe.[2] (The ring-necked pheasants seen in the present day were introduced later from East Asia.)


It is said that "the failure of Kolkhis to emerge as a strong kingdom or to be maintained as a province of Rome has been blamed on the pestilential climate of the Phasis Valley, a situation remarked upon by travelers down to modern times, when the swamps were finally drained.[3]".


The Rioni is the longest river wholly within the borders of Georgia. The river is 327 kilometres (203 mi) long, and its drainage basin covers about 13,400 square kilometres (5,200 sq mi).[4] It starts on the southern slopes of the Caucasus Mountains at 2,960 metres (9,710 ft) above sea level, north of the town Oni. Its largest tributaries are, from source to mouth: Jejora (left), Qvirila (left), Khanistsqali (left), Tskhenistsqali (right) and Tekhuri (right).

Phasis river at TaprobanaEdit

Stephanus of Byzantium writes that there was also another river which was called Phasis at Taprobana (Ancient Greek: Φᾶσις ἐν τῇ Ταπροβάνῃ).[5]


  1. ^ a b Heinz Heinen, Andrea Binsfeld, Stefan Pfeiffer. Vom hellenistischen Osten zum römischen Westen. Wiesbaden, Germany: Franz Steiner Verlag, 2006, pg. 324
  2. ^ Oxford English Dictionary, Draft Revision, September 2009
  3. ^ Robert H. Hewsen, Armenia: A Historical Atlas, 2001, page 38
  4. ^ Statistical Yearbook of Georgia: 2020, National Statistics Office of Georgia, Tbilisi, 2020, p. 12.
  5. ^ Stephanus of Byzantium, Ethnica, § Ph660.2