Guam History and Chamorro Heritage Day, also known as Guam Discovery Day is a national public holiday in Guam. Portuguese explorer Ferdinand Magellan landed on Guam on 6 March 1521, marking the first European contact.

Celebrated on first Monday of March each year, the day showcases culture and heritage of the native Chamorro people, the largest ethnic group in Guam, accounting for more than a third of the total population.