Holy Days of Obligation for the United States
On Sundays and other holy days of obligation, the faithful are obliged to participate in Mass. In so far as possible they are also to abstain from those works and affairs which hinder the worship to be rendered to God, the joy proper to the Lord's day, or the suitable relaxation of mind and body. (Canon 1247)
At their November 1991 meeting, the United States Conference of Catholic Bishops decided that whenever January 1, the Solemnity of Mary Mother of God, or August 15, the feast of the Assumption of the Blessed Virgin, or November 1, the Feast of All Saints, falls on a Saturday or a Monday, the obligation to attend Mass is lifted. Also, the Ascension of Our Lord, which falls on a Thursday, has been transferred to the following Sunday. However, parishes are to continue to observe these holydays by scheduling one or more Masses at a convenient time so that people who wish to participate are able to do so.
All Sundays of the year
Solemnity of Mary, Mother of God -January 1
The Ascension of Our Lord -40 days after Easter
The Assumption of the Blessed Virgin Mary -August 15
All Saint's Day -November 1
The Immaculate Conception of the Blessed Virgin Mary -December 8
Christmas, the Nativity of Our Lord -December 25
Holy Days are all listed on the Diocesan Calendar.