Lacanau and the Landes: Reading Europe's Straightest Sand Coast as a Single 230-Kilometre Line

There is a pattern we keep seeing when readers ask us to draw the French Atlantic between the Gironde estuary and the foot of the Pyrenees. They expect the usual coastal chart — headlands, coves, a rhythm of rock and inlet. What the coastline data returns instead, pulled from OpenStreetMap's natural=coastline layer across the Landes, is roughly 230 kilometres of near-continuous sand running almost due north-south, with Lacanau near the top of that line and Hossegor (spot at 43.6713, -1.4420) sitting just before it breaks. It is the straightest long coast in western Europe, and the shape explains almost everything else about it.

The Pattern: One Coastline Drawn With a Ruler

Export the natural=coastline polygon for the Aquitaine seaboard from an Overpass query and load it into any GIS viewer at continental zoom. The line does not wiggle. Between the mouth of the Gironde in the north and the town of Capbreton in the south, the shore holds a bearing within a few degrees of true north-south for the entire length. Lay a straightedge from Lacanau's beach down to Hossegor and the ruler kisses the sand for something on the order of 155 kilometres before either end drifts off. Extend the same ruler up past Lacanau to the estuary and down past Capbreton to the beginning of the rocky Basque coast and the total straight run pushes past 230 kilometres.

This is unusual. Most European coasts read as a negotiation between rock and sea — a shoreline that has been forced to accommodate the geology it sits on. Cornwall wraps around slate. Brittany fractures against granite. The Algarve carves cliffs out of limestone. Northern Spain is a comma of headlands. The southwest French coast, uniquely at this length, has almost no geology to negotiate with above the waterline. The rock is buried under sand, the sand is held in place by pine forest, and the boundary between land and water is drawn by the same physics that draws a beach berm anywhere — but drawn over and over, without interruption, at the scale of a small country.

The consequence for the reader-as-mapmaker is that the usual coastal vocabulary breaks down. There is no "Cap de Lacanau", no "Baie de Mimizan", no "Pointe de Seignosse". There is one long beach with different names printed on it at different mileposts. A cartographer drawing this coast learns quickly that the interesting information is not in the shoreline itself — the shoreline is a straight line — but in what sits behind it and what sits underneath it.

The Dune Wall That Made It Straight

Behind the straight line stands the second-largest continuous coastal dune system in Europe. It is not incidental to the shape of the coast — it is the reason the coast has that shape. Sand supplied by longshore drift from the Gironde and by onshore transport from a broad, shallow continental shelf has been piled by prevailing westerlies against a low-lying hinterland for the entire Holocene. Left to its own devices, the system migrates inland. That is what it was doing, aggressively, until the nineteenth century.

The intervention is documented and specific. Nicolas Brémontier's plan to fix the Landes dunes with a graduated planting of marram grass and maritime pine dates to the 1780s. The forestry programme that turned the plan into a landscape was formalised under Napoleon III's law of 19 June 1857, which required the drainage of the coastal marshes and the systematic afforestation of the department. What was a mobile sand sea became, within roughly a century, a straight seaward wall of dunes backed by the largest planted forest in western Europe — the Landes de Gascogne, more than 10,000 square kilometres of maritime pine.

The straightness of the coastline today is therefore partly natural and partly engineered. The Atlantic supplies the sand; the pines hold the dune; the dune holds the shore. Take away any element in that stack and the line becomes something else. Break the pine cover and the sand walks inland by tens of metres a decade — the Dune du Pilat near Arcachon, north of our study line, is Europe's tallest coastal dune precisely because it sits at a gap in the forest cover and continues to migrate. Draw the coast without its dune and you lose the ruler.

For the surf coast reader, the practical implication is that the beach breaks along this line — Lacanau, Le Porge, Mimizan, Contis, Moliets, Seignosse, Hossegor's northern stretches — all sit on the seaward face of the same landform. The sandbars that structure their waves are produced by the same longshore currents raking the same sediment. Different names, one system.

When the whole coast is one landform, the interesting map is not the shoreline. It is the seafloor and the forest, both of which are drawn nowhere the postcard looks.

Hossegor The print from this article · from €29.95 View the print →

The Trench Off Hossegor and Why the Line Bends Below It

At Hossegor the ruler stops working. The reason is offshore, invisible from the beach, and older than the forest by orders of magnitude.

The Gouf de Capbreton is a submarine canyon that begins within a few hundred metres of the shoreline at Capbreton — one of the closest canyon-to-shore approaches on any inhabited European coast. From the beach the seafloor drops from a few metres to several hundred over a horizontal distance that a coastal cartographer would draw as a hairline. The canyon then runs west-northwest into the abyssal plain of the Bay of Biscay, deepening as it goes. It is a documented feature on every hydrographic chart of the region and has been studied continuously since the nineteenth century.

The canyon does not create the coast's straightness — the canyon predates the dune system by millions of years — but it terminates it. Sand moving southward along the Landes coast under longshore drift reaches Capbreton and falls into the trench, which acts as a sediment sink. Below the canyon the coastal geology changes. The Pyrenean foothills reach the sea at Anglet. Sand gives way to rock. Beach gives way to cliffs and coves. Biarritz (spot at 43.4853, -1.5584) sits on that different coast — the same country, a different landform, and a different kind of coastline for the mapmaker to draw.

The canyon also explains why Hossegor sits where it sits in surf-cultural memory. Wave energy propagating in from the west encounters an abrupt bathymetric feature within sight of the beach; refraction over the canyon rim is documented in coastal-engineering literature; the resulting break at La Gravière is a product of that geometry rather than of anything specific about the beach in front of it. The wave is not made at the beach. The wave is made a kilometre offshore, over a trench that also happens to draw the punctuation mark at the end of the Landes sentence.

For the reader tracing the coast on a chart, this is the moment the story stops being about sand and starts being about basement geology. The ruler that carried Lacanau to Hossegor cannot be extended past Capbreton. What continues past that point is a different argument between land and sea, one that we have written about elsewhere in the context of Biarritz and the origins of European surf culture on rock coasts.

Reading the Sand Coast as a Single Cartographic Object

The invitation, then, is to stop thinking of the resort names along this line as separate places. Lacanau is not a destination. Neither is Mimizan, Moliets, Seignosse, or Hossegor. They are mileposts printed on the same continuous landform. Anyone who has walked the coastal footpath south from Lacanau knows the practical version of this claim: the beach does not end. The town ends, the parking ends, the lifeguard flags end, and then the beach continues, indistinguishable from the beach in front of the town you just left, for as many hours as you care to walk.

Drawn as one object, the Lacanau-to-Hossegor coast reveals what individual resort maps hide. It is a single hydraulic system. Sediment enters at the top from the Gironde and exits at the bottom into the Capbreton canyon. Wave energy arrives across the entire length at broadly similar angles because the shore is straight. The dune line rises and falls in elevation but never breaks. The pine forest sits behind the dune from end to end. The narrow coastal road that resort brochures call scenic is, in cartographic terms, a service road running along the landward flank of a single 230-kilometre object.

The consequences of drawing it this way are practical. A comparison of "Lacanau versus Hossegor" makes less sense the more of the coast you have on the same sheet of paper — the two towns are separated by mileage and by the accident of what got built where, not by any change in the shape of the coast between them. A study of "how the Landes coast is changing" makes more sense than it does elsewhere in Europe because the study object is genuinely singular. And a print of this coastline, drawn at true bearing and true scale from the OSM natural=coastline layer, is one of the very few coastal maps in Europe where the shoreline can be represented as a nearly straight line without any dishonesty toward the geography.

This is the coast we draw when we draw the Landes. The pattern is the map, and the map is the argument.

If you want the coast in the room as a physical object, our studio print of this line is in the studio shop, scaled and drawn from the same coastline data cited here.

This piece did not cover the ecology of the Landes de Gascogne forest as a landscape in its own right — the maritime pine monoculture is a separate story with its own history of fires, storms and replanting, and it deserves the space. It did not cover the modern coastal-erosion picture along the Aquitaine seaboard, which is active and well-mapped and would require its own data pass rather than a summary here. And it did not cover the pre-nineteenth-century human history of the coast — the shepherds on stilts, the pre-forest marshland — which is a cultural rather than a cartographic subject, and one better told with photographs than with contour lines.

Biarritz The print from this article · from €29.95 View the print →

FAQ

How long is the sand coast between the Gironde estuary and Capbreton?

Measured along the OpenStreetMap natural=coastline layer at continental zoom, the near-continuous sand run between the mouth of the Gironde in the north and the town of Capbreton in the south is on the order of 230 kilometres. The stretch between Lacanau and Hossegor alone — the part most surfers picture when they say "the Landes" — is roughly 155 kilometres. Both figures are the shore-following distance rather than straight-line distance, though on this coast the two are unusually close.

Why is the Landes coast so unusually straight compared with the rest of Europe?

Two reasons, one natural and one engineered. Naturally, the coast is fed by sand from the Gironde and from a broad, shallow shelf, with no coastal rock above the waterline to interrupt the drift. Engineered, the dune system behind the beach was fixed in place by systematic marram-and-pine planting from the late eighteenth century onward, formalised under Napoleon III's 1857 law. Together the sand supply and the fixed dune line let the shoreline draw itself as a near-straight edge.

What is the Gouf de Capbreton and why does it matter for this coast?

The Gouf de Capbreton is a submarine canyon whose head sits within a few hundred metres of the shoreline at Capbreton, near Hossegor. It is one of the closest canyon-to-shore approaches on any inhabited European coast. It matters here for two reasons: it acts as a sediment sink that terminates the long southward longshore-drift system of the Landes, and it modifies incoming swell over its rim in ways that shape the waves at Hossegor's beaches, notably La Gravière (spot at 43.6713, -1.4420).

Is the forest behind the beach natural or planted?

Planted, at scale. The Landes de Gascogne is one of the largest planted forests in western Europe. The programme grew out of Nicolas Brémontier's late-eighteenth-century dune-fixing plan and was made systematic under the French law of 19 June 1857, which required drainage of the coastal marshes and afforestation with maritime pine. What is now a forested hinterland was, before that intervention, a mobile sand sea and a chain of marshes.

Why does the coastline change character below Capbreton?

Because the geology changes. North of Capbreton the coast is sand held by dune held by planted forest, with basement rock buried well below the beach. Below the Gouf de Capbreton, the Pyrenean foothills reach the sea near Anglet, and the coastline becomes rock, cliff and cove. Biarritz (spot at 43.4853, -1.5584) sits on that rock coast. The transition is abrupt in landform terms and is visible on any hydrographic chart of the area.

Where does the coastline data used here come from?

The shoreline geometry cited in this piece is from OpenStreetMap's natural=coastline layer, extracted via the Overpass API and used under the Open Database License (ODbL). It is the same layer that underlies most modern open coastal cartography in Europe. It is not a substitute for a professional nautical chart for navigation, but for drawing coasts at scale it is the best openly licensed source available.

Can Lacanau and Hossegor really be treated as points on the same coast rather than separate destinations?

Cartographically, yes. They sit on the seaward face of the same continuous dune-and-forest landform, share the same longshore-drift system, and receive Atlantic swell across a nearly identical shore-bearing. The differences readers usually invoke — one is quieter, the other is a fixture of surf-competition history — are cultural and infrastructural rather than geographic. On a map drawn from the coastline data alone, without labels, it is not possible to tell one from the other.

Does the studio sell a print of this specific coastline?

Yes. The Lacanau-to-Hossegor sand coast is one of the coastlines we draw from the OpenStreetMap coastline layer at true bearing and true scale, and it is available as a print in the studio shop alongside our other European coast prints.