It crosses twelve communes, from upstream to downstream: Le Gouray (source), Plénée-Jugon, Dolo, Jugon-les-Lacs, Plorec-sur-Arguenon, Plédéliac, Pléven, Bourseul, Pluduno, Plancoët, Saint-Lormel, Créhen and Saint-Cast-le-Guildo (mouth).

[4] The Arguenon has four named tributary streams, one river and 10 unnamed tributaries including:[1] We can also add, according to the National Institute of Geographic and Forest Information or Géoportail, and since the Guébriand is not a river in its own right: The Arguenon has been observed in Jugon-les-Lacs since 1972 at station J1103010 L'Arguenon, at an altitude of 31 metres (102 ft) with a catchment area of 104 kilometres (64.62 mi).

[5] At low water the minimum flow rate of the watercourse recorded for three consecutive days in a month, during a five-year dry period, was 0.014 cubic metres per second (0.49 cu ft/s).

The depth of runoff in this part of the river's catchment area is 253 millimetres (10.0 in) annually, which is a little lower than the average in France.

The specific flow rate reaches 8.0 litres per second (106 imp gal/min) per 1 square kilometre (0.39 sq mi) of basin.

The Arguenon estuary is protected by a 381 hectares (940 acres) Zone naturelle d'intérêt écologique, faunistique et floristique.