Alba
The ruler of Alba was King Constantine I (Constantine the Wine-Bountiful), who had ruled since 862 and would continue to do so until 877.
Gwynedd
The ruler of Gwynedd was King Rhodri ap Merfyn (Rhodri the Great), who had ruled since 844 and would continue to do so until 873.
Mercia
The ruler of Mercia was King Burgræd, who had ruled since 842 and would continue to do so until 874.
Strathclyde
The ruler of Strathclyde at the beginning of 872 was King Arthgal map Dumnagual, who had ruled since 817. This year, King Rhun map Arthgal would take over.
Wessex
The ruler of Wessex was King Ælfræd (Alfred the Great), who had ruled since 871 and would continue to do so until 899.