César Chávez Day is observed in the United States on March 31 each year. It celebrates the birthday of César Estrada Chávez and it serves as a tribute to his commitment to social justice and respect for human dignity.

Maundy Thursday, also known as Holy Thursday, is a Christian observance in the United States. It is the day before Good Friday and takes place during Holy Week. It commemorates Jesus Christ’s last supper and the initiation of Holy Communion (the Eucharist), observed in many Christian churches.

Good Friday occurs two days before Easter Sunday in the United States. It is the day when Christians commemorate Jesus Christ's crucifixion, which plays an important part in the Christian faith. It is not a federal holiday in the United States, although it is a state holiday in some states.

Many Christians in the United States observe Holy Saturday, which falls between Good Friday and Easter Sunday. It commemorates the day when Jesus Christ lay in the tomb after his death, according to the Christian bible. It is also known as Easter Eve and is the last day of Lent.

Many Jewish communities in the United States mark the last day of Passover as the end of a Jewish holiday that celebrates the deliverance of Jewish people from slavery in Egypt. Passover is also known as Pesah, Pesach, or the Feast of Unleavened Bread.

Many Christians celebrate Jesus Christ's resurrection on Easter Sunday. The Easter date depends on the ecclesiastical approximation of the March equinox.

Easter Monday is the day after Easter Sunday. It is not a federal holiday in the United States of America (USA). Some Easter traditions continue on the Easter Monday, such as the egg rolling race at the White House.

National Tartan Day is a US observance on April 6 each year. It commemorates the Scottish Declaration of Independence, from which the American Declaration of Independence was modelled on. It also recognizes achievements of Americans of Scottish descent.

Librarians across the United States celebrate National Library Workers’ Day (NLWD) on the Tuesday of National Library Week, held in April every year.