Last year Mule Day didn't happen because of the Virus .But school's bar's church are reopening back up so let us all wear mask and let us. Have Mule Day .If Columbia CAN HAVE THE FAIR THAN WHY NOT MULE DAY IT'S ABOUT HISTORY .Every April, Maury County holds a Mule Day celebration. Held in Columbia, Tennessee, Mule Day had its beginnings as "Breeder's Day" in the 1840s. Farmers and livestock breeders would bring their animals to market every April to show, buy, and trade.