Davao de Oro Foundation Day is observed in the province of Davao de Oro in the Philippines every March 8. This special non-working holiday celebrates the founding anniversary of the province, which was officially created on March 7, 1998, after being separated from Davao del Norte. The region's history dates back to ancient times when various indigenous tribes settled in the Davao Gulf area, and it later became part of the Sultanate of Maguindanao. Spanish colonization began in the mid-19th century, leading to significant changes in governance and infrastructure, particularly during American administration. The name change from Compostela Valley to Davao de Oro was approved by 97% of voters in a plebiscite held in December 2019 to emphasize its connection to the Davao region. The day is marked by local celebrations that honor the province's rich history and cultural heritage.