Territory Day is observed on Christmas Island, a territory within the Commonwealth of Australia, on the first Monday in October. This public holiday commemorates the day Christmas Island was designated as an external territory of Australia on October 1, 1960. The island, located in the Indian Ocean, was discovered in 1643 by Captain William Mynors and was officially annexed by the British Crown in 1888. During World War II, it was occupied by Japan due to its phosphate deposits, but was liberated by British troops in 1947. The celebration of Territory Day allows islanders to enjoy an extended weekend, reflecting on their unique history and connection to Australia.