Shrove Tuesday is a term associated in English-speaking countries, especially the United Kingdom, Canada, Ireland, Australia, New Zealand, and parts of the United States for the day preceding Ash Wednesday, the first day of the season of fasting and prayer called Lent. The word shrove is the past tense of the English verb shrive, which means to obtain absolution for one's sins by way of confession and doing penance.
Mardi Gras (Fat Tuesday in French) in New Orleans, Louisiana, is a Carnival celebration well-known throughout the world. The New Orleans Carnival season, with roots in preparing for the start of the Christian season of Lent, starts after Twelfth Night, on Epiphany (January 6). It is a season of parades, balls (some of them masquerade balls), and king cake parties.
While Mardi Gras in the United States is not observed nationally across the country, a number of cities and regions in the U.S. have notable Carnival celebrations. Because of the French and Spanish colonial history of the settlements, the earliest Carnival celebrations occurred in Mobile, Alabama, Biloxi, Mississippi, New Orleans, Louisiana, and Pensacola, Florida which have each developed separate traditions. In addition, modern activities generally vary from city to city across the USA.