On this holy day of obligation, we commemorate that from the moment of her conception, the Blessed Virgin Mary was in a state of grace and free from all original sin. Mary, as the Immaculate Conception, is the patroness of the United States. Read more.

In 2019, this Solemnity is transferred from Sunday, December 8 to Monday, December 9, but the obligation to attend Mass does not follow. It is not a holy day of obligation in 2019.