THE SOLEMNITY OF THE IMMACULATE CONCEPTION
On December 8, we honor Mary, our Mother. The Solemnity of the Immaculate Conception is a Catholic feast celebrating Mary's conception without sin. Even though this feast day occurs in the liturgical season of Advent, which prepares for the birth of Our Lord Jesus Christ, the Immaculate Conception refers to the conception of Mary in the womb of her mother, St. Anne.
The Immaculate Conception should not be confused with the perpetual virginity of Mary or the virgin birth of Jesus.  It refers to the conception of Mary, by her mother, St. Anne.  It is the belief that the Virgin Mary was free of original sin from the moment of her conception.  Although the belief was widely held since the early Church, and often debated by medieval theologians, it was not formally proclaimed until December 8, 1854, by Pope Pius IX in his Papa Bull Ineffabilis Deus.
Because the Sundays of Advent take precedent over Immaculate Conception, this year December 8, 2024, falls on a Sunday during Advent.  Hence, the Solemnity’s date must be transferred to the following Monday (December 9). As a result, the observance of the Solemnity of the Immaculate Conception of the Blessed Virgin Mary, the Patronal Feast Day of the United States of America, will be transferred to Monday, December 9, 2024.
In recent years, when December 8 fell on a Sunday, it was the practice in our country to indicate that the obligation to attend Mass does not transfer with the liturgical observance. In fact, many of our liturgical calendars, and even our Ordo, state that it is "not a holy day of obligation this year."  However, we have been informed by the Vatican Dicastery for Legislative Texts that this solemnity “must be observed as a day of obligation on the day to which it is transferred.” 
Therefore, as is our practice at HFCC, there will be a Vigil Mass on Sunday, December 8 at 6:30 PM and on Monday, December 9, 2024, there will be a mass at 12:15 pm and 6:30 pm.