List of state leaders in 831

Asia

*Bohai/Balhae - Da Yizhen/Dae I-jin, King of Bohai/Balhae (830-857)
*China (Tang Dynasty) - Wenzong, Emperor of Tang China (826-840)
*Gurjara - Nagabhata II, Pratihara King of Gurjara (805-833)
*Japan (Heian Period) - Emperor Junna, Emperor of Japan (823-833)
*Silla - Heungdeok, King of Silla (826-836)

Europe

*Asturias - Alfonso II, King of Asturias (791-842)
*Dál Riata - Óengus, King of Dalriada (820–834)
*Bulgaria -
**Omurtag, Khan of Bulgaria (814–831)
**Malamir, Khan of Bulgaria (831–836)
*East Anglia¹ - Æthelstan, King of East Anglia (826–839)
*England - Egbert of Wessex, Bretwalda (802–839)
*Frankish Empire -
**Louis the Pious, Holy Roman Emperor (816-840)
**Lothair I, Holy Roman Emperor (823-855)
*Mercia - Wiglaf, King of Mercia (830–840)
*Northumbria¹ - Eanred, King of Northumbria (810–841)
*Ireland - Conchobar mac Donnchada, High King of Ireland (818–831)
*Picts - Óengus (II), King of the Picts (820–834)
*Strathclyde - Arthgal f Dyfnwal, King of Strathclyde (816–872)
*Venice - Giovanni I Participazio, Doge of Venice (829-837)
*Wales - Merfyn "Frych" ap Gwriad, King of Gwynedd (825–844)

Notes

#Though East Anglia, Northumbria and Mercia are traditionally perceived to have been in the heptarchy they were largely independent kingdoms until its conquest by the Danes in 869 and 867, respectively - where Mercia was conquered by Wessex in 874. All other members of the heptarchy had been conquered by Wessex and by this time had no form or king