Étang d'Aureilhan, Artificial pond in Landes, France

Étang d'Aureilhan is an artificial pond in the Landes region with a substantial water surface and moderate depth. It connects to surrounding waterways through natural channels that form part of the local water network.

The pond formed when the dune system of the Aquitaine coast, built between roughly 500 and 1000 AD and again from 1500, blocked the flow of streams. Neolithic flint tools and arrowheads found in dredged sand show people lived here before the water rose. Sanding reduced its surface from 875 ha in 1813 to 331 ha today; in 1857 draining it was considered, but Mimizan refused.

The lake's name comes from the commune of Aureilhan, which shares its surface with Mimizan, Sainte-Eulalie-en-Born and Saint-Paul-en-Born. On the Mimizan shore stands the Château Woolsack, and a planted promenade runs for 800 m along the bank. A 12 km footpath circles the whole lake.

A 12 km footpath circles the whole pond, and a planted promenade runs for 800 m along the Mimizan bank near the Château Woolsack. The Tuc de Houns rises close to the Saint-Paul-en-Born shore. Water in the pond is renewed in about a week, so levels and conditions shift quickly.

The lake is fed by the Rivière Sainte-Eulalie, which carries water from the lakes to the north, including Biscarrosse and Parentis. This inflow brings suspended sand that silts up the basin; the surface fell from 875 hectares in 1813 to 331 hectares today.