List of state leaders in 818

817 state leaders – Events of 818 – 819 state leaders – State leaders by year

Asia

• China (Tang Dynasty) - Xianzong, Emperor of Tang China (806–820)
• Gurjara - Nagabhata II, Pratihara King of Gurjara (805–833)
• Japan (Heian Period) - Emperor Saga, Emperor of Japan (809–823)
• Korea (North South States Period)
  • Balhae -
    1. Gan, King of Balhae (817–818)
    2. Seon, King of Balhae (818–830)
  • Silla - Heondeok, King of Silla (809–826)

Europe

• Bulgaria - Omurtag, Khan of the Bulgars (814–831)
• Byzantine Empire - Leo V the Armenian. Roman Emperor (813–820)
• Caucasus
  • Principate of Iberia - Ashot I Kuropalates (c. 813–830)
  • Principality of Kakheti - Grigol, Prince of Kakheti (786–827)
• Kingdom of Denmark - Horik I (813–854)
• England (Heptarchy) - Cenwulf of Mercia, Bretwalda (796–821)
  • Kingdom of Essex - Sigered (812–825)
  • Mercia - Cenwulf, King of Mercia (796–821) and East Anglia (c.799–821) and King of Kent (807–821)
  • Northumbria - Eanred, King of Northumbria (810–841)
  • Wessex - Egbert, King of Wessex (802–839)
• Frankish Empire -
  • Louis the Pious, King of the Franks and Senior Holy Roman Emperor (814–840)
  • Lothair I, King of Italy and Junior Holy Roman Emperor (817–855)
  • Aquitaine - Pepin I of Aquitaine, King of Aquitaine (817–838)
    • Gascony -
      1. Gassia I Semen, Duke of Gascony (816–818)
      2. Lop III Centullo of Gascony, Duke of Gascony (818–819)
    • Toulouse - Berengar the Wise, Count of Toulouse (816–835)
  • County of Barcelona - Berà (801–820)
  • Bavaria - Louis the German, King of Bavaria (817–843)
  • Littoral Croatia - Borna of Croatia, Prince of Littoral Croatia (c.810–821)
  • County of Nantes - Lambert I (818–831)
  • County of Urgell - Borell (798–820)
• Ireland - Áed Oirdnide, High King of Ireland (797–819)
  • Ailech - Aed Oirdnide mac Neill, King of Ailech (788–819)
  • Connacht - Diarmait mac Tommaltaig, King of Connacht (815–833)
  • Uí Maine -
  • Leinster -
    • Muiredach mac Brain, Co-king of Leinster (808–818)
    • Muiredach mac Ruadrach, Co-king of Leinster (808–829)
  • Kingdom of Mide - Conchobar mac Donnchado (803–833)
  • Ulaid - Cairell mac Fiachnai, King of Ulaid (810–819)
• Italy -
  1. Bernard, King of Italy (810–818)
  2. Lothair I, King of Italy and Junior Holy Roman Emperor (818–855)
  • Principality of Benevento - Sico of Benevento (817–832)
  • Papal States - Pope Paschal I (817–824)
  • Republic of Venice - Agnello Participazio, Doge of Venice (811–827)
• Pannonian Croatia - Ljudevit Posavski, Duke of the Pannonian Croats (c.810–823)
• Scotland
  • Picts - Caustantin, King of the Picts (787–820)
• Spain -
  • County of Aragon - Aznar I Galíndez - Count of Aragon (809–820)
  • Kingdom of Asturias - Alfonso II (791–842)
  • Caliphate of Córdoba - al-Hakam I (796–822)
• Wales -
  • Kingdom of Gwynedd - Hywel ap Rhodri Molwynog (816–825)
  • Kingdom of Powys - Cyngen ap Cadell (808–855)

Middle East

• Abbasid Caliphate - Al-Ma'mun, Caliph (813–833)
• Byzantine Empire - Leo V The Armenian (813–820)