This solemnity commemorates the fact that Mary, in view of her calling to be the Mother of Christ and in virtue of his merits, was preserved from the first moment of her conception from original sin and was filled with grace from the very beginning of her life. The official teaching of the Church says: “The most Blessed Virgin Mary was, from the moment of her conception, by a singular grace and privilege of almighty God and by virtue of the merits of Jesus Christ, Savior of the human race, preserved immune from all original sin.” [Catechism of the Catholic Church no. 491]
The feast of the Conception of Mary appeared in the Roman calendar in 1476. The present form of the feast dates from Dec. 8, 1854, when Pope Pius IX in 1854, defined the dogma of the Immaculate Conception.
In 1846, Mary was proclaimed patroness of the United States under this title.
This a Holy Day of Obligation. Please check your parish bulletin or website for the schedule of Masses.