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.
Alt Clut
The ruler of Alt Clut during this time was either King Dumnagual map Riderch (Dumnagaul IV) or King Arthgal map Dumnagual, the exact year of the succession is unknown.
East Anglia
The ruler of East Anglia was King Eadmund (Edmund the Martyr), who had ruled since 855 and would continue to do so until 869.
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.
Wessex
The ruler of Wessex was King Æthelræd I, who had ruled since 865 and would continue to do so until 871.