Ria de Mogro belongs to the municipality of Miengo, and is part of the Natural Park of the Dunes of Liencres. Nearby is the "Abra del Pas" golf course, surrounded by forests and fine sand dunes.
It is one of the largest dune systems of the Cantabrian coast, which houses a rich fauna (waterfowl and migratory birds, lizards, snakes, amphibians, tritons, etc.) and flora (maritime pine dunes and other species adapted to live in the sand ).


The park of the Dunes of Liencres has two beaches: Valdearenas ( the big one) is the one on the left and a smaller beach, called Canallave. There is then a third beach on the shore of river Pas, at the foot of the pine forest planted on the dunes.

On the left side of the mouth of the Pas River are naturists who take advantage of the privacy of the dunes, the area offers much tranquillity and the huge pine trees are great if you are looking for shade.