Martin Luther King Jr. Day is a federal holiday in the United States, celebrated on the third Monday of January each year.

The holiday honors the civil rights leader Martin Luther King Jr., who played a key role in the American civil rights movement during the 1950s and 1960s.

Martin Luther King Jr. Day was first observed as a federal holiday on January 20, 1986, making it one of the newest holidays in the country.

Martin Luther King Jr. Day  is a "day on, not a day off," emphasizing the importance of using the day for acts of service, education, and reflection rather than simply taking it as a day of rest.

 Martin Luther King Jr. Day  is not only celebrated in the United States but also observed in some other countries to honor King's global impact on human rights.

The day is often seen as a time to reflect on and celebrate the accomplishments of the civil rights movement, as well as to promote equality and justice.