Catholic Holy Days, in brief

Paraphrasing from http://www.creighton.edu/~alackamp/holydays/answer.html:

The 1983 Code of Canon Law identifies Sunday as "the primordial holy day of obligation" in the universal Church. In addition to Sunday there are 10 other days of obligation, 6 of which are observed in the US:

  1. The Nativity of the Lord Jesus Christ (Christmas)
  2. The Epiphany (Jan. 6.)
  3. The Ascension (40 days after Easter)
  4. Holy Mary, the Mother of God (octave day of Christmas, Jan. 1)
  5. The Immaculate Conception (Dec. 8)
  6. The Assumption (Aug. 15)
  7. All Saints (Nov. 1)
The Bishop can suppress or transfer the observance of these days, after approval from the Apostolic See (i.e. the Vatican)