What is the list of each Holy day of obligation in the United States?
Some Holy days in the United States include The Ascension of Our Lord, All Saints Day, The Solemnity of the Immaculate Conception and Christmas. Others include The Assumption of the Blessed Virgin Mary, and Solemnity of Mary, the Mother of God. Read more from http://catholicism.about.com/od/holydaysandholidays/tp/Holy-Days-Of-Obligation-United-States.htm.
There are dozens. You should probably check the Catholic Church's website, since days of obligation are a uniquely Catholic belief.