Mondarrain (French pronunciation:[mɔ̃daʁɛ̃]; Arranomendi in Basque) is a mountain in the French Basque Country, south of Espelette and south-west of Itxassou in the province of Labourd, peaking at 749 metres (2,457 ft) altitude.
To prevent Marquess of Wellington's army invading France in 1813, Marshal Soult built a line of fortifications and entrenchments along the river Nivelle from the sea inland to fortified rocks on Mount Mondarrain.[1] The lines were breached during the Battle of Nivelle 10 November 1813.[2]