The next upcoming All Saints Day is on Monday November 1st, 2021.
All Saints day also known as All Hallows, Solemnity of All Saints and Feast of All Saints is celebrated November 1st in the West and the first Sunday after Pentecost in the East. It honors all the Saints and often is celebrated through a feast. The day celebrates that there is a spiritual connection between those in heaven and the living. All Saints' Day is not a national federal holiday but is and observance for Christians to recognize all the Saints in the church.
Pope Gregory IV in 837 made all Saints' Day an official holiday. There is speculation about the event being held on November 1, which is the same day as the pagan Festival of the Dead, which would compete with All Saints' Day. Others say, All Saints' Day got its start back in the fourth century where Greek Christians celebrated a festival on the first Sunday after Pentecost in honor of Saints. Today it is a nationally celebrated holiday.