Festivities of Oseja Activity · Oseja, Aranda, Zaragoza Image of Oseja, not of the place itself. The patronal festival of Oseja (Zaragoza) is celebrated on 3 February in honour of San Blas, with night bonfires, and on 15 and 16 August for the Asunción and San Roque, with performances of popular music. On the last weekend of June the pilgrimage to the Virgen de la Sierra takes place. The village also celebrates, on 13 December, the feast of Santa Lucía, with communal bonfires and grilled meat. Photo: Wikipedia / Wikimedia Commons (CC BY-SA) What to see and do in Oseja