Saint Pierre and Miquelon's geography: old rock joined by young sand

Where the archipelago sits off Newfoundland

The islands lie in the north-west Atlantic at the entrance to Fortune Bay, off the south coast of Newfoundland and close to the edge of the Grand Banks. Saint-Pierre is 19 km from Point May at the tip of the Burin Peninsula, and the Canadian Green Island lies about 10 km east of it, roughly halfway across. Paris is a long way off: the IEDOM report on the territory for 2024 puts it at 4,300 km, the territorial civil service wiki of the CNFPT at 4,750 km, and Brest, the nearest city in metropolitan France, is 3,819 km away according to English Wikipedia.

Eight islands and islets make up the archipelago, with a land area of 242 km² and a coastline of about 120 km. Only two are inhabited all year. Saint-Pierre, 26 km² with the islets beside it, holds the harbour, the town and the great majority of the people. Across a strait about 6 km wide lies Miquelon-Langlade, 216 km², which is in fact three former islands joined by sand: Le Cap in the north-west, Grande Miquelon in the middle and Langlade, also called Petite Miquelon, in the south. Around Saint-Pierre sit Île aux Marins, Île aux Pigeons, Île aux Vainqueurs and the two Colombiers, all inhabited at one time or another and all empty of permanent residents now.

How old rock and ice shaped the islands

Like Newfoundland and Nova Scotia, the islands belong to the north-eastern end of the Appalachians. French Wikipedia and the IEDOM report describe three different grounds. Saint-Pierre and the south of Grande Miquelon are volcanic, mainly rhyolite with breccias, andesite and basalt, the stone that prehistoric visitors came to quarry for tools. Langlade and the Cap peninsula are metamorphic, and Langlade is an old worn-down plateau cut by short rivers, the Belle Rivière the longest of them, running south to north. Trilobite fossils have been found there.

The last glaciation planed all of it down. The islands are low: the highest point is the Morne de la Grande Montagne on Grande Miquelon at 240 m, and Saint-Pierre rises to 210 m. What the ice left is bare rock with a thin cover of peat, ponds and bogs, and the coasts are cut into steep cliffs, up to 25 m high on the east coast of Grande Miquelon. The CNFPT wiki adds a human cause: the soil, poor to begin with, has been worn further by excessive clearing of trees since the seventeenth century. French Wikipedia records Langlade as already largely cleared of trees by the middle of the nineteenth century, and quotes the Revue des eaux et forêts on the islands' imports of 303,000 francs' worth of timber in 1865 against 120,000 francs exported.

Low soft coasts of sand and shingle make up about a third of the shoreline, according to the Conservatoire du littoral, a pattern of barrier beaches with ponds behind them. The rest is rock, volcanic and metamorphic cliffs and moraine.

How a sand isthmus joined Miquelon to Langlade

The isthmus is the archipelago's most recent piece of land. The Conservatoire du littoral, which protects 1,391 hectares of it, describes a sedimentary strip formed from the material the retreating glaciers left about 10,000 years ago, which closed for good only at the end of the eighteenth century. In the eighteenth century a boat could still pass between Miquelon and Langlade. French Wikipedia dates the join to 1783, and English Wikipedia notes that a storm once broke the strip for several decades before the currents rebuilt it. The IEDOM report describes it as formed and strengthened by stranded ships since the eighteenth century, and more than 500 wrecks are recorded along the isthmus alone.

Its length depends on who measured it. English Wikipedia's main article gives 10 km, its article on Miquelon-Langlade 12 km, as do the Conservatoire and the IEDOM, and the geography articles in both languages give 13 km. Its width runs from 6 to 100 metres. A second, shorter tombolo about 3 km long ties Grande Miquelon to Le Cap.

What the Grand Barachois holds

Behind the northern part of the isthmus lies the Grand Barachois, a brackish lagoon of about 1,000 hectares that empties to sand banks at low tide. Harbour seals breed and rest on its banks, a colony of several hundred animals according to the Conservatoire, and a group of grey seals returns each year to the beach at its mouth. Ducks winter on it, the American black duck feeding on its eelgrass, and twelve species of shorebird pass through in the autumn migration. A guide from the Maison de la nature told La 1ère that about forty harbour seals could be counted from a single spot on the shore.

The strait between Langlade and Saint-Pierre had a name of its own until about 1900: the Gueule d'Enfer, the Mouth of Hell. More than 600 shipwrecks have been recorded around the islands since 1800.

Why the climate is colder than the latitude

The archipelago lies at about 47 degrees north, the latitude of the Vendée on the French Atlantic coast, and its climate has nothing of the Vendée in it. The islands sit under polar air masses and in the cold Labrador Current, where it meets the warmer water of the Gulf Stream. English Wikipedia classes the climate as subarctic, Dfc in the Köppen scheme, on the edge of a cold oceanic climate because the winters are mild for that class. The seasons lag: September is warmer than June and March colder than December. Spring and early summer are foggy and cool, late summer and early autumn the sunniest part of the year, and the wind is strong in spring and autumn.

The long-run figures in English Wikipedia and the measurements Météo-France made for 2024, as the IEDOM reports them, sit side by side.

The year 2024 also set a June record of 25.2 °C. In February a nor'easter dropped 45 to 50 cm of snow, the most since the winter of 2004. Gusts passed 100.8 km/h on 15 days of the year and reached at least 75.6 km/h on 75. Fog comes mostly in June and July.

What lives on bare islands and in their waters

French territory has one boreal forest, and it is here. The IEDOM, quoting the Office national des forêts, gives it less than 3,000 hectares, mostly conifers, with balsam fir making up 83.5% of it, beside black and white spruce. On the dunes nothing grows taller than stunted alder and wild roses. The bogs carry pitcher plants, sphagnum and sedge, and the islanders gather strawberries, blueberries and the berry known locally as plate-bière. Three mammals were brought in for hunting: the snowshoe hare in 1881, the white-tailed deer in 1953 and the Arctic hare in 1982. The OFB records damage to balsam fir from the deer.

Birds are the largest group, with more than 330 species recorded according to the IEDOM, among them the snowy owl, the bald eagle, the common eider and the harlequin duck. The waters off southern Saint-Pierre, a hunting and wildlife reserve, are one of the two main wintering grounds of the harlequin duck in eastern North America with Cape St. Mary's in Newfoundland, according to the OFB, for a population of no more than 7,000 birds. Whales migrating towards Greenland pass the coasts every spring.

How the seabird counts on Grand Colombier changed

The islet of Grand Colombier north of Saint-Pierre is the archipelago's great seabird colony, and two recent counts disagree sharply. The IEDOM report for 2024 gives more than 400,000 pairs in all, including 363,787 pairs of Leach's storm petrel and 9,543 pairs of Atlantic puffin, with 1,500 pairs of razorbill and 7,100 of common murre. The OFB, after a new inventory with the CNRS in 2025, gives about 88,000 puffin pairs against roughly 10,000 before, and puts the storm petrel at 120,000 pairs, a fall.

The territory has little formal protection. The OFB notes that there is no marine protected area and no nature reserve, only the two hunting and wildlife reserves, beside 40 zones of recognised ecological interest. In 2025 a first marine teaching area for schoolchildren was set up on the Grand Barachois.

Why the village of Miquelon has to move

The village of Miquelon stands at the junction of Grande Miquelon and Le Cap, on a strip of ground about two metres above the sea, with water on both sides. Novethic reports that it has faced rising water and coastal erosion since the early 2000s. In December 2014 the president of France, visiting, announced a coastal risk plan that banned almost all new building in the village, and it was approved in 2018. Two storms ten days apart in November 2018 flooded the village from below, through the water table, and the researcher Xénia Philippenko describes that as the moment opinion turned. In a survey of 300 islanders in the summer of 2019, 89% favoured moving the village.

Hurricane Fiona brushed the archipelago in September 2022 before hitting Newfoundland, and Envies de ville reports that it hurried the plan. The new site lies inland on higher ground, 1.5 km from the old village by Novethic's account and 2 km by Envies de ville's, and about 20 metres above the sea against about 2 for the old village. The state offered to buy back the village's buildings, about 400 of them. The IEDOM records that the interministerial committee for overseas France of July 2023 granted a first €1.5 million, that €3 million in all was committed to the first stage, that connection works began in September 2024 and that the first 14 plots went on sale in October 2024.

The isthmus has its own problem. The road along it is the only land link between Miquelon and Langlade and carries supplies to the summer houses at Anse du Gouvernement, and heavy swell and spring tides keep breaking into it. The Conservatoire adds that free-roaming horses grazing the dunes speed up the erosion, and has been replanting the dune line since 2006.

Where the sea zone and the shelf end

Under the 1992 arbitral award the islands' territorial sea runs to 12 nautical miles, and their economic zone extends to 24 miles on the west with a corridor reaching south across the Canadian zone, as the history article describes. Beneath that water the continental shelf continues. France's submission of April 2014 to the United Nations Commission on the Limits of the Continental Shelf describes a passive margin shared with Canada and the United States, formed when the North American and African plates separated after rifting began in the Triassic, and a sea floor built up by glaciers and, since at least the Upper Pliocene, by the delta at the mouth of the Laurentian Channel.

France filed preliminary information on 8 May 2009 and its partial submission in April 2014, claiming shelf beyond 200 nautical miles. Canada rejected, in a note of 9 November 2009, "any claim by the French Republic to any maritime area, including any areas of continental shelf" in the region, citing the 1992 award. The commission does not examine a submission while a maritime dispute exists without the consent of both parties, and France's own summary records that the dispute exists. This catalogue records it and takes no position on it.