Former Arén municipality: Arén, Campamento de Arén, Sobrecastell, Berganuy, Claraválls, Puifel and Soliva.
Former Cornudella de Baliera municipality (merged in 1965): Rivera de Vall, San Martín, El Sas, Casa Consistorial, Puimolar, L'Hostalet, Vilaplana, Soperún, Iscles, Suerri and Tresserra.
Former Betesa municipality (merged in 1966): Betesa, Santa Eulalia, Los Molinos and Obís.
Trivia
The prehistoric crocodilian Arenysuchus was named after the municipality.
The duck billed dinosaur Arenysaurus was also named for this place.
^As shown in the Legislative Decree 2/2006Archived 2009-04-23 at the Wayback Machine of 27 December, of the Government of Aragon, by the revised text of the Law on Comarcal Demarcation of Aragon is approved.