Portomarín is a municipality in the province Lugo, in the autonomous community of Galicia, Spain.

It is one of the towns in the pilgrimage route known as the French Way, part of the Camino de Santiago.

The town of Portomarín was built next to a Roman bridge over the Miño River and rebuilt during the Middle Ages.

In the 1960s the Miño River was dammed to create the Belesar reservoir, putting the old village of Portomarín under water.

In the seasons when the dam is at low level, the remains of ancient buildings, the waterfront and the old bridge are still visible.