Like this will ever be complete. Also includes failed states, puppet states, claimed nations, and micronations, for kicks.
- Aachen (Free Imperial City) (Aachen 1306–1801)
- Abbasid Caliphate (Kufa 750–762, Baghdad 762–796, Raqqa 796–809, Baghdad 809–836, Samarra 836–892, Baghdad 892–1258, Cairo 1261–1517)
- Abhira (Kingdom) (Valkha 203–467)
- Abkhazia (Kingdom) (Anacopia 778–786, Kutaisi 786–1008)
- Abkhazia (Principality) (Sokhumi 1463–1570)
- Abkhazia (Autonomous Republic) (Sokhumi 1992–1993, *Tbilisi 1993–2006, Chkhalta 2006–2008, *Tbilisi 2008–)
- Abkhazia (Republic) (Sokhumi 1992–)
- Achaea (Principality) (Andravida 1205-1249, Mystras 1249-1261)
- Acre (Republic) (Porto Acre 1899–1900, 1900, 1903)
- Adal (Sultanate) (Zeila 1415–1420, Dakkar 1420–1520, Harar 1520–1577, Aussa 1577)
- Lucerne (Canton) (Lucerne 1386–1798)
- Philippines (Republic) (Manila 1946–)
- Samo's Empire (Wogastisburg 631–658)
- Switzerland (Bern 1848–)
- Tibet (Empire) (Lhasa 618–842)
- Tibet (Ganden Phodrang) (Lhasa 1642–1959, *Dharamsala 1959–)
- Wabanaki Confederacy (Qonasqamkuk 1606–1862, 1993–)