Damrong Rajanubhab Day is observed in Thailand on December 1 each year. This national observance commemorates the passing of Prince Damrong Rajanubhab in 1943. Born on June 21, 1862, he was the son of King Mongkut and is recognized for his significant contributions to the modern Thai educational system, which included mandatory education for ministers and authorities and the establishment of schools. As Minister of Education, he implemented reforms that unified minor provinces and created the monthon administrative structure, reducing the autonomy of provincial governors. Since 2001, the day has been celebrated to honor his legacy and contributions to education and governance in Thailand.