National Prom Day is observed in the United States on March 31 every year, celebrating the significance of prom night for high school students. The holiday was founded in 2016 by PromGirl, an online retailer specializing in teen special occasion fashions, and aims to support nonprofits that enhance the lives of teens. Prom night, which originated in the 19th century as a college event, has evolved into a major high school tradition characterized by formal attire, promposals, and various customs such as crowning a prom queen. Celebrations may include planning and shopping for prom outfits, sharing prom memories on social media with the hashtag #NationalPromDay, and donating dresses or suits to those in need. In its inaugural year, National Prom Day supported Students Against Destructive Decisions (SADD), focusing on issues like bullying and substance abuse, and has since partnered with other youth-focused organizations.