Andalucía, Aragon, Asturias, Castile and León, Murcia: New Year's Day is a public holiday in all countries that observe the Gregorian calendar, with the exception of Israel
Basque Country, Extremadura, Murcia, Navarra, Valenciana: Feast day of St. Joseph. Joseph was the husband of the Blessed Virgin Mary and the foster father of Jesus
Andalucía, Aragon, Asturias, Balearic Islands, Basque Country, Canary Islands, Cantabria, Castile and León, Castilla-La Mancha, Ceuta, Extremadura, Galicia, La Rioja, Madrid, Melilla, Murcia, Navarra: Also Known as Holy Thursday, Maundy Thursday commemorates the last supper and established the ceremony known as the Eucharist
Balearic Islands, Basque Country, Catalonia, La Rioja, Navarra, Valenciana: Easter is probably the most important holiday of the Christian year, celebrating the Resurrection of Jesus
Valenciana: Saint Vincent is the patron saint of Valencia. He was martyred during the Christian persecutions of Emperor Diocletian around the year 304.
Ceuta, Melilla: Eid al-Adha, the Feast of Sacrifice is the most important feast in the Muslim calendar. It celebrates the willingness of the Prophet Ibrahim to sacrifice his son Ishmael in submission to Allah's command, before he was stopped by Allah.
Catalonia: December 26th is the Feast of St. Stephen in Western Christianity. It is observed as a second day of Christmas holidays in several countries.
Notes
Public holidays are taken on the day they fall and not moved to the following weekend, if they fall on a Saturday or Sunday.
The list of regional holidays changes every year, partly because of national holidays falling on Sundays.