Arcachon is located at Longitude 01°10'03”W and Latitude 44°39'34”N on the Atlantic Coast in the Gironde department of the Aquitaine region in France. The nearest large city is Bordeaux. Being a seaside resort, Arcachon is at an altitude of 0 to 45 metres, has a land area of 7.56 km2and a population of 11,459. Close by, on the Basin d'Arcachon, is Europe's largest sand dune, the Dune du Pyla (or Pilat), nearly 3 kilometres long, 500 metres wide reaching 107 metres in height, and moving inland at rate of 5 metres per annum.
Arcachon Bay receives freshwater from the Eyre river, draining the Landes plateau, and is linked to the Atlantic Ocean by the narrows. 115 m2 of mud-flats are revealed when the 155 m2 high tide waters of Arcachon Bay reduce to 40 m2 at low tide. Arcachon Bay's climate changes little from one season to the next (13 Celsius on average). These mild conditions are home to 300 species of nesting or migrating birds. Arcachon was the first French port to fit out steam trawlers in the 19th century and the Bay of Arcachon is Europe's leading oyster-breeding nursery.