List of state leaders in 859

858 state leaders - Events of 859 - 860 state leaders - State leaders by year

Asia

• China (Tang Dynasty) -
  1. Xuanzong, Emperor of Tang China (846–859)
  2. Yizong, Emperor of Tang China (859–873)
• Gurjara - Mihira Bhoja I, Pratihara King of Gurjara (c. 836–886)
• Japan (Heian Period) - Emperor Seiwa, emperor of Japan (858–876)
• Korea (North South States Period)
  • Balhae - Dae Geonhwang, King of Balhae (857–871)
  • Silla - Heonan, King of Silla (857–861)

Europe

• Bulgaria - Boris I, Khan of the Bulgars (852–889)
• Byzantine Empire - Michael III (842–867)
• Caucasus
  • Principate of Iberia - Bagrat I Kuropalates (830–876)
  • Principality of Kakheti - Samuel, Prince of Kakheti (839–861)
• Littoral Croatia - Trpimir I, Duke of Littoral Croatia (845–864)
• Kingdom of Denmark - Horik II (854–c. 866)
• England (Heptarchy) -
  • Kingdom of East Anglia - Edmund the Martyr (854–869)
  • Mercia - Burgred, King of Mercia (852–874)
  • Northumbria - Osberht, King of Northumbria (849–862/863)
  • Wessex - Æthelbald, King of Wessex (856–860)
• East Francia - Louis the German, King of East Francia (843–876)
  • Duchy of Saxony - Liudolf, Duke of Saxony (844–866)
  • Thuringia - Thakulf, Duke of Thuringia (849–873)
• West Francia - Charles the Bald, King of West Francia (843–877)
  • County of Angoulême - Turpion (839–863)
  • Duchy of Aquitaine - Ranulf I, Duke of Aquitaine (854–866)
  • Kingdom of Aquitaine -
    • Pepin II of Aquitaine, King of Aquitaine (854–864)
    • Charles the Child, King of Aquitaine (855–866)
  • County of Auxerre - Conrad I (859–864)
  • Barcelona - Humfrid, Count of Barcelona (858–865)
  • Duchy of Brittany - Salomon (857–874)
  • Gascony - Sans II Sancion of Gascony, Duke of Gascony (836–864)
  • County of Maine - Rorgon II (853–865)
  • Poitiers - Ranulf I, Count of Poitiers (854–866)
  • County of Toulouse - Raymond I (852–863)
  • Troyes - Rudolph I, Count of Troyes (858–866)
  • Urgell - Solomon, Count of Urgell (848–869)
• Ireland - Máel Sechnaill mac Máele Ruanaid, High King of Ireland (846–862)
  • Ailech - Áed Findliath, King of Ailech (c. 855–879)
  • Connacht - Mugron mac Máel Cothaid, King of Connacht (848–872)
  • Hy-Many -
  • Leinster -
  • Mide - Máel Sechnaill mac Maíl Ruanaid, King of Mide (845–862)
  • Munster - Máel Gualae mac Donngaile, King of Munster (856–859)
  • Osraige - Cerball mac Dúnlainge, King of Osraige (842–888)
  • Ulaid -
  • Cathalán mac Indrechtaig, Co-king of Ulaid (857–871)
  • Lethlobar mac Loingsig, Co-king of Ulaid (857–873)
• Italy - Louis II, King of Italy and Holy Roman Emperor (855–875)
  • Principality of Benevento - Adelchis, Prince of Benevento (854–878)
  • County of Capua - Lando I (843–861)
  • March of Friuli - Eberhard (846–863)
  • Duchy of Gaeta - Constantine, Hypatus of Gaeta (839–866)
  • Duchy of Naples - Sergius I (840–864)
  • Papal States - Pope Nicholas I (858–867)
  • Principality of Salerno - Adhemar (853–861)
  • Duchy of Spoleto - Guy I (842–860)
  • March of Tuscany - Adalbert I (847–886)
  • Venice - Pietro Tradonico, Doge of Venice (836–864)
• Lotharingia - Lothair II, King of Lotharingia (855–869)
• Great Moravia - Rastislav, Prince of Great Moravia (846–870)
• Provence - Charles, King of Provence (855–863)
• Scotland
  • Picts - Donald I, King of the Picts (858–862)
• Serbia - Mutimir, Grand Zhupan of Serbia (850–891)
• Spain -
  • County of Aragon - Galindo Aznárez I (844–867)
  • Kingdom of Asturias - Ordoño I (850–866)
  • Caliphate of Córdoba - Muhammad I (852–886)
  • Kingdom of Pamplona - García Íñiguez (851/852–882)
• Wales -
  • Kingdom of Gwynedd - Rhodri Mawr (844–878)
  • Kingdom of Powys - Rhodri Mawr (855–878)