The Catholic Holy Days of Obligation are our most important feast days. They are the principal liturgical feasts that
honor the mysteries of the Lord, the Virgin Mary, and the saints. Rejoice! Catholics know that these are the most
important days of the year and of course the best way to celebrate them is to celebrate Holy Mass with all the angels
and saints!

On December 13, 1991 the members of the National Conference of Catholic Bishops of the United States of America
made the following general decree concerning holy days of obligation for Latin rite Catholics:

In addition to Sunday, the days to be observed as holy days of obligation in the Latin Rite dioceses of the United States
of America, in conformity with canon 1246, are as follows:

2017 Holy Days (Canon 1246, §2)

Sunday, January 1 - Solemnity of Mary, Mother of God - a holy day of obligation      
Thursday, May 25 - Ascension of Jesus - a holy day of obligation                         
Tuesday, August 1 - Assumption of the Blessed Virgin Mary - a holy day of obligation
Wednesday, November 1  - All Saints' Day - a holy day of obligation             
Friday, December 8 - Feast of the Immaculate Conception - a holy day of obligation
Monday, December 25 - Christmas - a holy day of obligation

Whenever January 1, the solemnity of Mary, Mother of God, or August 15, the solemnity of the Assumption,
or November 1, the solemnity of All Saints, falls on a Saturday or on a Monday, the precept to attend Mass is
abrogated.

This decree of the Conference of Bishops was approved and confirmed by the Apostolic See by a decree of the
Congregation for Bishops (Prot. N. 296/84), signed by Bernardin Cardinal Gantin, prefect of the Congregation,
and dated July 4, 1992.

As President of the National Conference of Catholic Bishops, I hereby declare that the effective date of this
decree for all the Latin rite dioceses of the United States of America will be January 1, 1993, the solemnity of
Mary, Mother of God.

Given at the offices of the National Conference of Catholic Bishops in Washington, DC, November 17, 1992.


+ Daniel E. Pilarczyk
Archbishop of Cincinnati
President of the National Conference of Catholic Bishops

Robert N. Lynch
General Secretary

http://www.usccb.org/beliefs-and-teachings/what-we-believe/canon-law/complementary-norms/canon-1246.cfm
What are the Holy Days of Obligation?