The Vallès Oriental Regional Archive (ACVO), inaugurated on 30 September 2005, is part of the Regional Archives Network of the Catalan Goverment (Generalitat de Catalunya) and is managed jointly by the Vallès Oriental Regional Council and the Granollers City Council, in accordance with the agreement signed on 29 December of the same year between the Department of Culture, the Regional Council and the Granollers City Council.

The capacity of the ACVO is 10,000 linear metres of shelving, of which 6,600 are currently occupied. Among the documentary collections deposited in the archive, we can highlight those of the city councils of Aiguafreda, Castellterçol, Granollers, Santa Eulàlia de Ronçana and Tagamanent; also, the documentation of the Vallès Oriental Regional Council, the funds of the archive of notarial protocols of the district of Granollers, of the courts of first instance of Granollers and Mollet, of the Regional Office of the Department of Agriculture or of the agrarian chambers of various towns.

Also worth noting is the photographic fund of the magazine Sport Comarcal; the patrimonial or farmhouse funds, which contain nearly 400 parchments ranging from the 12th to the 17th century, or the fund of the barony of Montbui, a jurisdiction made up of Santa Eulàlia, Bigues, Riells, l’Ametlla, Lliçà d’Amunt, Palaudàries and Sant Mateu de Montbui. There are also several personal funds.

The ACVO also guards an important newspaper library fund (regional magazines and municipal bulletins), as well as a collection of local monographs that are constantly being updated. In addition, it shares facilities with the Municipal Archive of Granollers, which has deposited part of its documentary, newspaper and image collection there. A large part of the ACVO's collection can be viewed online through the Arxius en Línia and XAC Premsa portals.