Cesar Chavez Day Poster, United States Department of Labor publications
Cesar Chavez Day is always celebrated on his birthday, 31 March.
It is not a public holiday, but is a state holiday in California. It is either an optional or commemorative day in nine other states - Arizona, Colorado, Illinois, Michigan, New Mexico, Texas, Utah, Wisconsin and Rhode Island.
In Arizona, government offices may be closed and government employees are encouraged to volunteer in the local community on the day.
Cesar Chavez was born on 31 March 1927, in Yuma, Arizona. His family had moved to Northern California to work as migrant farm workers after losing their land in the great depression.
He served in the US navy for two years at the end of the Second World War, returning to work on farms until 1952, when he became involved with the Community Service Organization, a Latino civil rights group, rising to become its national director by 1958.
In 1962, Chavez became a cofounder of the National Farm Workers' Association (now the United Farm Workers).
In this new role, Chavez became the best known Latino American civil rights activist. Leading the struggle for better rights for farm workers, his aggressive but nonviolent tactics made the farm workers' struggle a moral cause with wide support. His also gained national awareness as he went on several hunger strikes to highlight his campaigns.
Cesar Chavez died on 23 April 1993 of unspecified natural causes, with some believing that his death may have been caused in part by his hunger strikes.