Holy days of obligation are days set aside by the Church when the faithful attend Mass. In addition to Sundays, the days observed as holy days of obligation in the United States are:
January 1 – Mary, Mother of God *
Ascension of Our Lord ** (see below)
August 15 – Assumption of the Blessed Virgin Mary *
November 1 – All Saints *
December 8 – Immaculate Conception of the Blessed Virgin Mary
December 25 – Nativity of Our Lord Jesus Christ
Each Sunday, the faithful gather for worship in honor of Christ’s Resurrection. The additional holy days of obligation listed above are days dedicated to important events connected to the life of Jesus or persons linked to him. As it states in the Code of Canon Law, the faithful are obliged to participate in Mass. Insofar 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).
* Please note: By decision of the United States Conference of Bishops and confirmation by the Holy See, whenever the Solemnities of Mary, Mother of God (January 1), the Assumption of the Blessed Virgin Mary (August 15), or All Saints (November 1) fall on a Saturday or a Monday, the obligation to attend Mass is lifted. --taken/sourced from the Diocese of Richmond, VA
** Note: In most archdioceses and dioceses within the United States, the Ascension of the Lord is transferred to the Seventh Sunday of Easter. In the archdioceses and dioceses within the Ecclesiastical Provinces of Boston, Hartford, New York, Newark, Omaha, and Philadelphia, the Ascension of the Lord always falls on the preceding Thursday of the Sixth Week of Easter and is a Holyday of Obligation. -- taken/sourced from USCCB
The Diocese of Providence is part of the Ecclesiastical Province of Hartford and Ascension is celebrated on sixth Thursday after Easter, and is a Holy Day of Obligation.