Her sister, Edythe Scott Bagley told the Atlanta Journal Constitution that King died at a holistic hospital in Rosarito Beach, Mexico, 16 miles south of San Diego
Although she suffered a debilitating stroke and heart attack last August, she made a surprise appearance this month at the Salute to Greatness dinner held in her husband's honor in Atlanta by the King Center for Non-violent Social Change, which she founded in 1968.
Born in Heiberger, Ala., on April 27, 1927, King met her future husband in Boston, and they married in 1953. They moved to Montgomery, Ala., which was to become the hotbed of the U.S. civil rights movement, in which the couple became deeply involved. But on April 4, 1968, her husband was assassinated in Memphis.
Apart from creating and running the foundation, she also led the campaign to make Martin Luther King's Jan. 15 birthday a national holiday in the United States, which Congress supported, and the first national observance of the holiday took place in 1986.
She is survived by her four children.