Andorra's geography: one river basin with two doors

How three Andorran valleys join into one river

Britannica describes Andorra as a cluster of mountain valleys whose streams unite to form the Valira, and the arrangement is simple enough to draw from memory. The Valira del Nord rises near El Serrat in the north-west and runs south through Les Salines, Arans, La Cortinada, Sornàs, Ordino and La Massana, where the Tristaina river comes in. The Valira d'Orient rises near Grau Roig in the east and runs down through Soldeu, Canillo and Encamp. The two meet at Les Escaldes, where the Madriu also joins, and below that confluence the river is the Gran Valira.

On a map the three arms make a Y. Its fork sits at Escaldes-Engordany and its stem points south, and the stem is short. The Gran Valira leaves the country in the south near the road crossing into Spain, and the lowest ground in Andorra lies on that stretch, at the Riu Runer confluence, 840 metres above sea level. The average elevation of the country is 1,996 metres, so the point where the water leaves stands more than a kilometre below the mean height of the land it drains.

The word "almost" covers several much smaller basins that straddle the borders with France and Spain. The most notable lies below Pic de Maià, where the Sant Josep flows east out of the country into France and joins the Ariège, a tributary in the Garonne basin, which drains to the Atlantic. The Pas de la Casa area in the east also sits on the Atlantic side of the drainage divide, while the Valira valleys lie on the Mediterranean side. The watershed between two seas therefore runs just inside Andorra's eastern edge.

Standing water is scattered through the heights. Andorra has 172 lakes, and the Estanys de Juclar near Pic de Noé in the north-east cover 23 hectares. The Estany de l'Estanyó, east of El Serrat, is reachable only by a hiking trail. In the record, water accounts for 0.43% of the country's surface.

Where the Andorran border follows the ridgelines

All of Andorra is mountain, and 65 peaks stand inside it. The border runs for 56.6 kilometres against France and 63.7 kilometres against Spain, and both lines are strung between summits. Coma Pedrosa, at 2,942 metres, stands in the north-west near both borders. Pic de Médécourbe, at 2,914 metres, is the western tripoint where the three states meet.

The French line, read west to east, crosses Pic de Cataperdis at 2,805 metres, Pic de Tristaina at 2,878 and Pic de Font Blanca at 2,903 in the north-west, then Pic de la Serrera at 2,914 in the north and Roc Mélé at 2,811 in the east. The Spanish line runs from Médécourbe and Coma Pedrosa through the Port de Cabús at 2,301 metres and on to Pic Negre at 2,665 and Pic de la Portelleta at 2,905 in the south. Pic d'Envalira, at 2,825 metres, and Pic dels Pessons, at 2,865, stand in the east near where the two neighbours' borders meet.

The extreme points fix the outline. The northernmost is Basers de Font Blanca, the southernmost is Conangle on the Riu Runer, the westernmost is the Coll de l'Aquell and the easternmost is where the Riu de la Palomera meets the Ariège. The geographical centre lies near Encamp. Inside that frame the country covers 468 square kilometres.

The two main roads out of Andorra cross that line by very different routes. The CG-1 follows the Gran Valira south from Andorra la Vella to the Spanish border near Sant Julià de Lòria. The CG-2 climbs east to the French border near El Pas de la Casa, a village at 2,100 metres, and now passes through the Envalira Tunnel on the way.

How altitude sets the Andorran climate

Wikipedia classes the climate as high-mountain Mediterranean, shaped by both Mediterranean and Atlantic circulation. The valleys have winters more severe, humidity lower and summers slightly cooler than the lowlands of the two neighbours, and differences in altitude, relief and valley orientation break the country into numerous microclimates.

Height does most of the sorting. The average annual temperature is 11 degrees Celsius at Sant Julià de Lòria in the south, 8 at La Massana in the centre and 2 at Arcalis in the north. At Escaldes-Engordany the average daily high and low run 28 and 15 degrees in July, and 11 and minus 2 in January. Mean annual temperatures are estimated to fall below zero above about 2,600 metres, and the alpine tree line runs at about 2,100 to 2,400 metres, above which the climate is alpine and the ground is alpine tundra.

Precipitation averages 1,071.9 millimetres a year across the country and rises both with height and from south to north. Sant Julià de Lòria, the driest parish, takes about 800 millimetres; Canillo, the wettest, about 1,100; and the highest ground can exceed 1,220. January and February tend to be the driest months, and May, June and November the wettest. Summer brings few rainy days, but the rain that falls comes with thunderstorms and can be very heavy. Snow covers the northern valleys completely for several months.

The divide shows up in the weather too. The Pas de la Casa area, on the Atlantic side, is exposed to moist northerly air, while the Valira valleys on the Mediterranean side are generally more sheltered and sunnier. The country averages 300 days of sunshine a year, and the average daily peak insolation runs from 1,150 watts per square metre in June to 280 in December.

The long-term series shows warming. Between 1950 and 2015 the annual mean temperature rose by 0.18 degrees Celsius per decade, and by 0.29 per decade in summer. Further warming is expected to reduce snowfall and shorten the ski season, which usually runs from late November to early April, and more artificial snowmaking would draw harder on water. The IMF staff statement of 9 March 2026 lists rising temperatures and more frequent extreme weather among the risks to tourism and infrastructure.

Where Andorra's forest came back

Three published figures give the share of Andorra under forest, and they differ because they measure different things at different dates.

The Observatori de la Muntanya d'Andorra puts forest at about 39% of the country, on a habitat map drawn from aerial photographs of 2012. Its series goes back to 1948. Forest grew by 2.5% between 1948 and 1972 and by 12.7% between 1972 and 1995, then held steady to 2012, with broadleaf woodland gaining while conifer and riverside woodland lost slightly. The observatory attributes the growth to the abandonment of fields and pastures, which the trees then took over. It adds that the 1948 values are estimates, because that year's forest mapping was drawn at a coarser resolution, and that more forest has not meant better forest.

The same 2012 land-cover map, as Wikipedia reports it, classes about 40% of the country as dense woodland, 25% as meadow and grassland, 13% as scree and 9% as shrubland. A third figure, from the international forest series, gives about 34% of the land area, 16,000 hectares in 2020, unchanged from 1990, all of it naturally regenerating.

Tree species change with height. Downy oak and Scots pine grow in the montane belt, mountain pine and silver fir in the subalpine belt, and alpine grassland takes the highest ground. Phytogeographers place the country in the Atlantic European province of the Circumboreal Region, and the WWF assigns all of it to a single ecoregion, the Pyrenees conifer and mixed forests.

The abandoned fields had never been many. Britannica records that only a tiny proportion of the land was ever cultivable, and that the traditional economy rested on sheep and on modest harvests of tobacco, rye, wheat, olives, grapes and potatoes. As those plots went out of use, the slopes above the valley floors went back to wood.

Why Andorrans live on the valley floors

Wikipedia's geography of Andorra puts the population mainly along the valley floors, and every figure that follows is a count of people living on a narrow strip of flat ground at the bottom of the Y. The record puts the population at 89,752 as of 30 June 2026. Britannica gives a density of 191.5 people per square kilometre for 2026, a figure that divides them across the whole 468 square kilometres, peaks and scree included.

The country has grown into its valleys quickly. The population was about 5,000 in 1900. The statistics department counted 89,165 residents on 31 January 2026, 1,862 more than a year earlier, a rise of 2.1%. The communal censuses kept by the parishes registered 94,222 people on the same date. The urban share stood at 88.9% in 2025 in the record, and Andorra la Vella, at 1,023 metres, had 24,042 inhabitants on 1 January 2023.

The Constitution of 1993 names seven parishes, and Escaldes-Engordany, created in 1978, is the newest. Growth in the year to January 2026 fell unevenly across them.

The shape of that table follows the Y. Canillo and Encamp lie up the Valira d'Orient, Ordino and La Massana up the Valira del Nord, and Escaldes-Engordany at the fork. Andorra la Vella and Sant Julià de Lòria lie south of the fork, on the CG-1 towards Spain. Canillo, high on the eastern arm, added 7.0% in the year to January 2026, and Sant Julià de Lòria, the parish that holds the southern exit, added 1.1% over the same year.

How two roads carry Andorran traffic

Until the 20th century Andorra had very limited transport links to the outside world, and its physical isolation shaped how it developed. The road network now runs to 279 kilometres, of which 76 are unpaved. There is no railway and no airport for fixed-wing aircraft inside the borders. The nearest station, Andorre-L'Hospitalet, lies 10 kilometres east on the French side, and the Andorra-La Seu d'Urgell airport lies in Spain, 12 kilometres south of the border. Heliports at La Massana, Arinsal and Escaldes-Engordany carry commercial helicopter services.

Road traffic uses the CG-1 and the CG-2. Vehicle entries at the borders came to 4,312,664 in 2024, according to the statistics department as Diari d'Andorra reported it, and visitors to 9,646,656 that year. Entries of cars rose 2.7% at the French border and 0.8% at the Riu Runer crossing in the south.

In December 2024 the watershed decided where that traffic went. The French authorities closed the approaches during episodes of snow and wind, and car entries from France fell by 9.3% on the month while heavy vehicles fell by 62.3%. Traffic moved to the southern border, where car entries rose 13.2%. That month the river exit at 840 metres stayed open through weather that shut the road over the divide.

What the slopes send down on the valleys

Landslides and avalanches are the main natural hazards, and both land on the valley floors where the people are. Avalanche risk runs from midwinter to early summer. The methods used against it include controlled blasting, snow nets, snow fences, deflectors, rigid barriers and snow compaction.

Two avalanches stand in the record. In 1970, after a storm left 2 metres of new snow on the pack above Pas de la Casa, a powder avalanche broke at 2,640 metres on the upper slopes of Pic d'Envalira, ran down a 35-degree slope across six bends of the old CG-2 and hit the village, killing a nurse. Protective works were studied as the ski resort grew, and it took until 1985 for 250 metres of windbreaks and 500 metres of snow fences to be installed.

At 19:00 on 8 February 1996 a powder avalanche that followed several days of heavy snow and high winds fell on Arinsal. The village and its visitors had been evacuated an hour and a half earlier, and nobody died, but cars, hotels and flats were destroyed or badly damaged. The government then built a snow dam across the Arinsal valley, 16 metres high and 320 metres wide, from 115,000 cubic metres of soil and 11,000 of rock, at a cost of 52 million francs.

Landslides tend to follow heavy rain. On 25 January 2008, in the evening rush hour, 4,000 cubic metres of loose soil and rock came down onto the CG-3 between La Massana and Ordino, closing it for three days and burying a car park; the cause was traced to ground excavated for that car park thirty years before. On 7 July 2009 a rockfall dropped 200 metres onto the CG-3 near the Pont Pla Tunnel, and nets caught most of it.

Earthquakes are frequent but small. Those centred inside Andorra tend to stay below magnitude 2, and there is no historical record of a damaging one there, though the Catalan earthquake of 1428 shook the wider Pyrenees and a magnitude 4.2 shock at Bagnères-de-Luchon on 5 October 1999 was widely felt in the valleys. The government has studied the possibility of a damaging earthquake.

Which Andorran valley still has no road

One side valley in the south-east has stayed outside the pattern of the rest. The Madriu-Perafita-Claror Valley covers 4,247 hectares, a little more than 9% of the national territory by UNESCO's figure, with a buffer zone of 4,092 hectares around it. Its upper part is an exposed glacial landscape of steep cliffs, rock glaciers and lake glaciers. Lower down it narrows and becomes wooded, and at the bottom the river runs through a short gorge before it reaches the Valira d'Orient near Les Escaldes. The Perafita-Claror valley joins it from the south-west.

UNESCO calls it "the last place in the country not to have roads". It inscribed the valley as a cultural landscape in 2004 and extended the buffer zone to the Spanish border in 2006. What the listing protects is a way of using high ground: stone huts with vaulted roofs still used by shepherds, stables and cheese dairies, terraced fields, partly paved trails and the remains of iron smelting in Catalan forges. Four communities own land inside the property under a communal system that UNESCO dates to the 13th century, and its management plan came into force on 28 December 2011.

The communal system has a constitutional form. Article 80 of the 1993 Constitution gives the parish councils powers over the delimitation of communal territory, natural resources, the cadastral register and local planning, and Article 31 charges the state with the rational use of the soil.

The protected areas extend the same pattern north. The parish of Ordino was designated a UNESCO biosphere reserve in 2020, covering 8,473 hectares with a population of 5,278 in UNESCO's entry for the 2020 designation, forested with Scots pine, fir, sessile oak and mountain pine, and holding the bearded vulture, the Pyrenean desman and Aurelio's rock lizard. The natural parks of the Sorteny and Comapedrosa valleys, together with the Madriu, make up the country's network of protected natural areas, and all three are Ramsar sites covering 6,870 hectares in total.