The Lanterne rises within the "parc naturel régional des Ballons des Vosges", in the "commune" of La Lanterne-et-les-Armonts in the "département" of Haute-Saône. It flows westward, then northwestward, then northward, and finally southwestward. It receives fast-flowing tributaries from the Massif des Vosges in the north. It flows to the south of Luxeuil-les-Bains and Saint-Loup-sur-Semouse. The watershed of the Lanterne is scattered with over 1,000 bodies of water, notably in the "Plateau des Mille Étangs" (plateau of a thousand ponds) in the Vosges Massif. The Lanterne joins the Saône at Conflandey, just downstream of the hydrological station at Fleurey-lès-Faverney. The confluence occurs a few kilometres upstream of the antique town of Port-sur-Saône. The Lanterne's course includes numerous diversions, once used for irrigation, drinking water and water mills. Initially the Lanterne was crossed at Faverney via a ford, then by a ferry boat. Following a capsizing on 30 May 1746, which resulted in drownings, a bridge was built. Cherlieu Abbey owns fisheries at Conflans. The Lanterne flows through the following towns and villages: The Lanterne is fed by the following tributaries and sub-tributaries: The annual mean flow rate of the Lanterne, calculated over 45 years of measurements at Fleurey-lès-Faverney as of 2008 (1964–2008), is 22.1 m³/s for a watershed of 1,020 km². The river exhibits seasonal fluctuations in flow rate, with winter floods from 32.4 to 37.3 m³/s from December to March inclusive, and weak flow in summer, in July/August/September, characterised by a decrease in the average monthly flow rate to 6.86 m³ in August. Average monthly flow rate (m³/s) measured at the Fleurey-lès-Faverney hydrological station - data calculated from 45 years of measurements  At low water, the 3-year low instantaneous flow rate can drop to 1.7 m³/s in the case of a dry five-year period.