La Sénia is a town and municipality in the Montsià region located on the border with the Valencian Country.
The name comes from the Arabic language saniya (flour mill), passed to the Romance form azenia in the Middle Ages. The town shares its name with the Sénia river, which runs through the municipality.
The Sénia river constitutes the link between Catalonia and the Valencian Community and is the administrative limit of both communities. Leaving aside the limits between communities, the river is the gateway to the Benifassà Tenure and the natural access to the Els Ports massif.