Independence Declaration Day in Montenegro is observed on June 3, commemorating the formal declaration of independence by the Parliament of Montenegro in 2006. This day follows the independence referendum held on May 21, 2006, where 55.5% of voters supported independence from the State Union of Serbia and Montenegro. While Independence Day is a national holiday celebrated on May 21, Independence Declaration Day serves as an observance rather than a public holiday. The historical context of Montenegro's independence traces back to 1918 when it was absorbed by the Kingdom of Serbia, and later, it became part of Yugoslavia. The day is marked by various commemorative activities, although specific customs or celebrations are not detailed in the source.