Independence Day is an annual holiday commemorating the formal adoption by the Continental Congress of the Declaration of Independence on July 4, 1776, in Philadelphia. Although the signing of the Declaration was not completed until August, the Fourth of July holiday has been accepted as the official anniversary of United States independence and is celebrated in all states and territories of the U.S.

The Fourth of July is traditionally celebrated publicly with parades and pageants, patriotic speeches, and organised firing of guns and cannons and displays of fireworks. Family picnics and outings are a feature of private Fourth of July celebrations.

Thanksgiving Day, a legal holiday in the U.S., was first celebrated in early colonial times in New England. The actual origin is probably the harvest festivals that are traditional in many parts of the world. After the first harvest was completed by the Plymouth colonists in 1621, Governor William Bradford proclaimed a day of thanksgiving.

In 1863 President Abraham Lincoln appointed a day of thanksgiving, and since then each president has issued a Thanksgiving Day proclamation, generally designating the fourth Thursday of November as a holiday.

New Year's Day is the first day of the year, January 1 in the Gregorian calendar. In the Middle Ages most European countries used the Julian calendar and observed New Year's Day on March 25, called Annunciation Day and celebrated as the birth to the Son of God. With the introduction of the Gregorian calendar in 1582, Roman Catholic countries began to celebrate New Year's Day on January 1.

The custom of visiting friends, relatives and neighbours on New Year's Day is one of the Old World traditions that has taken on a new form in the United States. A favourite place to see the old year out is New York City's Time Square.

Christmas is an annual festival, held on December 25, to celebrate the Nativity, or birth of Christ. The Christmas tree, an evergreen trimmed with lights and other decorations, is derived from the so-called paradise tree, symbolising Eden.

Saint Valentine's Day, a holiday honouring lovers, is celebrated on February 14. There is a custom of sending greeting cards or gifts to express affection. The cards, known as valentines, are often designed with hearts to symbolise love. The holiday probably derives from the ancient Roman feast of Lupercalis (February 15). The festival gradually became associated with the feast day (February 14) of two Roman martyrs, both named St. Valentine, who lived in the 3rd century. St. Valentine has traditionally been regarded as the patron saint of lovers.