The idea for setting aside a day to honor and appreciate what single parents do began in 1984 with an article written by Janice Moglen, a single mother of two. She hoped that this day would some day be recognized in the same way we celebrate parents on Mothers' Day and Fathers' Day. She began a collaboration with Parents Without Partners to petition states to recognize those parents who are both mother and father to their children.
She was only partially successful in her efforts to bring awareness and appreciation to the parents who fill both roles. While Ronald Reagan did officially designate March 21, 1984 as National Single Parents' Day, it hasn't gained widespread recognition. You can help change that by contacting your own state and national representatives and let them know how you feel about the mothers and fathers who are taking on the challenges of child-rearing without the support of a partner.
Single Parents' Day is not printed on the calendar hanging in my office, but I will recognize it just the same. To all you parents going it alone, I applaud you and appreciate the sacrifices you make every single day.