Margaret Winonah Beamer Myers was an American political activist, who, in 1961 at the age of 19, became a Freedom Rider. Freedom Riders were civil rights activists who rode interstate buses into the segregated southern United States in 1961 and following years to challenge the non-enforcement of the United States Supreme Court decisions Irene Morgan v. Commonwealth of Virginia (1946) and Boynton v. Virginia (1960). She was arrested in Jackson, Mississippi and spent almost six months in Mississippi State Penitentiary, better known as Parchman Farm, the oldest prison and the only maximum-security prison for men in the state of Mississippi. Of all the Freedom Riders, white or black, Winonah Beamer served the longest sentence and was the only Freedom Rider who served her full term.