Which lake has a main input and output from the Rhone river ?
Lake Geneva is divided into three parts because of its different reasons of formation ( sedimentation , tectonic folding , glacial erosion ) : " Haut Lac " ( Upper Lake ) , the eastern part from the Rhone estuary to the line of Meillerie – Rivaz " Grand Lac " ( Large Lake ) , the largest and deepest basin with the lake 's largest width " Petit Lac " ( Small Lake ) , the most south - west , narrower and less deep part from Yvoire – Promenthoux next Prangins to the exit in Geneva According to the Swiss Federal Office of Topography , swisstopo , " Lac de Genève " designates that part of the " Petit Lac " , which lies within the cantonal borders of Geneva ( excluding the cantonal exclave Céligny ) , so about from Versoix – Hermance to the Rhone outflow in Geneva .