The lighthouse of Trézien is located inland 500 meters from the shore and 1.5 km from the tip of Corsen, in the town of Plouarzel in Finistere. This directional lighthouse lined up on the Kermorvan lighthouse allows for a hundred years to cross safely the channel of the furnace. Its frustoconical shaft, painted white towards the south, is finished by a cantilever made of consoles assembled by arches supporting a cylindrical stone balustrade. The tower rests on a frustoconical basement stone masonry granite, from the Aber-Ildut. It can be visited in summer. Nearby is the CROSS-Corsen (Regional Operational Monitoring and Rescue Center), which monitors offshore traffic and coordinates sea rescue in the Western Channel.
