Mary Cain, American runner

Mary Cecilia Cain is an American-born Irish professional middle distance runner from Bronxville, New York. Cain was the 2014 World Junior Champion in the 3000 meter event. She is the youngest American athlete ever to represent the United States at a track and field World Championships meet after competing in the 2013 World Championships in Athletics in Moscow aged 17 years and 3 months.

May 3 is the 123rd day of the year in the Gregorian calendar; 242 days remain until the end of the year.