List of state leaders in 825

Asia

*Bohai/Balhae - Da Renxiu/Dae In-su, King of Bohai/Balhae (818?-830)
*China (Tang Dynasty) - Jingzong, Emperor of Tang China (824-826)
*Gurjara - Nagabhata II, Pratihara King of Gurjara (805-833)
*Japan (Heian Period) - Emperor Junna, Emperor of Japan (823-833)
*Silla - Heondeok, King of Silla (809-826)

Europe

*Asturias - Alfonso II, King of Asturias (791-842)
*Bulgaria - Omurtag, Khan of Bulgaria (814–831)
*Dál Riata - Óengus, King of Dalriada (820–834)
*East Anglia¹ - Beornwulf, King of East Anglia (823–826)
*England² - Egbert of Wessex, Bretwalda (802–839)
*Essex² - Sigered, King of Essex (798–825)
*Frankish Empire -
**Louis the Pious, Holy Roman Emperor (816-840)
**Lothair I, Holy Roman Emperor (823-855)
*Kent² - Baldred, King of Kent (823–825)
*Mercia - Beornwulf, King of Mercia (823–826)
*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 - Agnello Participazio, Doge of Venice (811-827)
*Wales -
*#Hywel "Farf-Fehinog" ab Caradog, King of Gwynedd (814–825)
*#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
#825 is the year of the establishment of England, following the conquest of Essex and Kent by Wessex. This followed other conquests.