The fortress of Dumbarton was the stronghold of the kingdom of Alclud until the Vikings destroyed the fortress after a four-month siege in 870. This led to the emergence of the new kingdom of Strathclyde. The title "king of the Britons of Srath Clúade" was first used in 872. Dumbarton was later the county town of the county of Dumbartonshire. The name comes from the Scottish Gaelic "Dùn Breatainn" meaning "fort of the Brythons (Britons)". Alexander II granted the status of royal burgh in 1222.

Dumbarton Castle has the longest recorded history of any stronghold in Scotland. It sits on a volcanic plug of basalt known as Dumbarton Rock.


The Dumbarton Rock Bowling Club, located just below the castle, has the best manicured lawn of the area, located just below the castke, has the best manicured lawn of the area