Mollet del Vallès is a municipality in the comarca of the Vallès Oriental in Catalonia, Spain. It is situated in the valley of the Besòs river, and is …Mollet del Vallès is a municipality in the comarca of the Vallès Oriental in Catalonia, Spain. It is situated in the valley of the Besòs river, and is an important communications hub from Barcelona towards the north: the AP-7 Motorway passes through the municipality, as do the Renfe railway lines to Vic and Puigcerdà and to Girona and Portbou. The town is also served by the C-17 highway.