Oiartzun (Basque: Oiartzun, Spanish: Oyarzun) is a town and municipality located in the Basque Country, in the province of Gipuzkoa lying at the foot of the massif Aiako Harria.The name traces back to the Oiasso or Oiarso of the Roman period, an important town dedicated to mining and marine activities. However, it has been pinpointed actually in the current border town of Irun, so the name may have referred to the whole area.