Louis Francois Marie Aleno de Saint Aloüarn (25 July 1738 – 27 October 1772) was a notable French mariner and explorer.
St Aloüarn was the first European to make a formal, but now unrecognised, claim of sovereignty — on behalf of France — over the west coast of Australia, which was known at the time as "New Holland".
Much of this west coast had already been charted by other mariners from the Netherlands, following a landing by Dirk Hartog in 1616, who left a commemorative plaque recording his visit.
James Cook, in 1770, had charted and claimed the east coast for Britain.
When St Aloüarn visited New Holland in 1772, neither British nor Dutch officials had issued a formal claim over this western part of New Holland.
However, the French claim over Western Australia was never secured by a permanent settlement.