River
Semois
210 km from source to mouth · France and Belgium.
France and BelgiumFlows into Meuse
In numbers
Length
210km
Average flow
35m³/s
Basin
1,329km²
Drop
126m
from 261 m to 135 m
Countries
2
The journey
From source to mouth
210 km of river and 18 stops on the way: 16 towns and cities on its banks, dams, bridges and the tributaries that feed it.
- 0 kmArlonat 261 m
- 0 kmAthus8,028 people
- 0 kmLamadelaine3,219 people
- 1 kmRodange7,774 people
- 1 kmAubange14,932 people
- 5 kmMont-Saint-Martin8,509 people
- 7 kmHerserange4,438 people
- 8 kmLongwy14,695 people
- 11 kmRéhon3,287 people
- 15 kmLexy3,107 people
- 31 kmLonguyon5,773 people
- 104 kmCarignan3,249 people
- 134 kmSedan20,620 people
- 165 kmVillers-Semeuse3,547 people
- 180 kmCharleville-Mézières52,415 people
- 193 kmNouzonville6,817 people
- 202 kmPont de Claies
- 202 kmVresse-sur-Semois2,641 people
- 202 kmRuaumolintributary
- 210 kmMeuseat 135 m
Water level along the river (RiverATLAS; the height is exaggerated). Towns: GeoNames and Wikidata; bridges, dams and tributaries: Wikidata.
River in Belgium and France, tributary of the Meuse
At the mouth it carries 35 m³/s on average: an Olympic pool every 71 seconds. It drops from 261 m to 135 m, 0.6 m per kilometre on average. Its basin covers 1,329 km², about the size of MQ. 538,000 people live in it. Highest water: from December to February. No large dam holds it back: it is one of the world's free-flowing rivers.
Where to start
- Charleville-MézièresLargest city on its banks · 52,415 people
- Brussels South Charleroi Airport (CRL)Nearest airport with scheduled flights, 79 km from the cityCar hire at CRL airport (Charleroi)Discover Cars · Affiliate link↗
- On the water35 ferry piers, marinas, boat rentals and boat ramps along the river (OpenStreetMap)
- From May to SeptemberThe best months to visit
Semois, month by month
Highest water: from December to February
Best months to visit: from May to September.
From about 30 m³/s in the lowest month to 150 m³/s in the highest. An estimate: the monthly flow is modelled from the lowest and highest months of WaterGAP (RiverATLAS, 1971–2000) and the rain and snow along the river (WorldClim). Dams change the real rhythm. The chip is the average air temperature; below it, the month's rain.
Plan the trip
Plan the trip: boat trips, a bed by the river, a car
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The basin
Semois: the basin in numbers
7,873 km² of land send their water to this river. This is what lives on it.
- 538,000people live in the basin
- 68/km²people per km²
- 288maverage altitude of the basin
- 863mmof rain a year (basin average)
- 9.2°Caverage air temperature
- 10%protected areas
What covers the basin
- 19% Forest
- 28% Cropland
- 24% Pasture
- 3% Towns and cities
RiverATLAS (HydroATLAS v1.0, CC BY 4.0): land cover, people, protected areas, glaciers and dams over the whole basin upstream of the mouth.
Along the river
Semois: what you find on the way
- 36WeirsBarrage de Romery, Barrage à clapet Mazarin, Barrage gonflable de Mézières and 33 more
- 40LocksCanal de la Meuse, Canal des Ardennes, Dérivation de Romery and 37 more
- 3Waterfalls
- 25Boat ramps
- 7MarinasHalte fluviale municipale, Halte Nautique Pont-à-Bar Services, Halte Fluviale de Lumes and 4 more
From OpenStreetMap, within 1.7 km of the river. Not mapped is not the same as not there.
Cross-checked with our atlases
Semois in our other atlases
What our sister atlases know about the waterfalls on this river, the lakes it flows through, the beaches at its mouth, the mountains where it rises and the islands off its mouth.
1mountain at the sourcePeakyas
Mountains at the source (1)
Within 15 km of the source, by Peakyas
- Montagne de Stockem5.0 km away367m
From space
The source and the mouth, seen from orbit
Sentinel-2 cloudless 2016 by EOX IT Services GmbH (contains modified Copernicus Sentinel data 2016), CC BY 4.0. The glowing line is the river as drawn by RiverATLAS.
Photos
Semois in pictures
Tributaries
Where it flows, and what flows into it
It flows into
Meuse
The Netherlands950 km230 m³/sTributaries (7)
Also: Rulles, Vierre, Membrette, Antrogne, Ruaumolin, Saint-Jean, Aleines
Nearby
Rivers nearby
Luxembourg
GermanyWhere these numbers come from
| Name, length, places | Wikidata (Q303621) · CC0 |
|---|---|
| Course, profile, basin | RiverATLAS v1.0 (HydroATLAS, Linke et al. 2019) · CC BY 4.0 — followed from the source to the mouth given by Wikidata |
| Flow | WaterGAP (RiverATLAS), 1971–2000 · CC BY 4.0 |
| Climate along the river | WorldClim (RiverATLAS), 1970–2000 · CC BY 4.0 |
| Towns, bridges, dams | Wikidata · CC0; GeoNames · CC BY 4.0 |
| Along the river | © OpenStreetMap contributors · ODbL |
| Images | EOX Sentinel-2 cloudless 2016 · CC BY 4.0; Wikimedia Commons |
| Our other atlases | Peakyas — Wikidata · CC0; © OpenStreetMap contributors · ODbL; GeoNames · CC BY 4.0; HydroLAKES · CC BY 4.0; NOAA OISST |
Every source and licence is on the data sources page.
The family
Do you prefer beaches, lakes, mountains, waterfalls, islands, rivers or canyons?
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