{{Flagicon image|Flag_of_San_Marino_%28civil%29.svg}} San Marino – Most Serene Republic of San Marino
{{flagcountry|Kingdom of Sarawak|1848}} – Kingdom of Sarawak
{{flagcountry|Kingdom of Sardinia|1848}} – Kingdom of Sardinia {{small|(to March 17)}}
{{Flagicon image|Flagge_Herzogtum_Sachsen-Coburg-Gotha_(1826-1911).svg}} Saxe-Altenburg – Duchy of Saxe-Altenburg
{{Flagicon image|Flagge_Herzogtum_Sachsen-Coburg-Gotha_%281911-1920%29.svg}} Saxe-Coburg-Gotha – Duchy of Saxe-Coburg and Gotha
{{noflag}} Saxe-Lauenburg – Duchy of Saxe-Lauenburg, also Duchy of Lauenburg
{{Flagicon image|Flagge_Herzogtum_Sachsen-Meiningen.svg}} Saxe-Meiningen – Duchy of Saxe-Meiningen
{{Flagicon image|Flagge_Gro%C3%9Fherzogtum_Sachsen-Weimar-Eisenach_%281813-1897%29.svg}} Saxe-Weimar-Eisenach – Grand Duchy of Saxe-Weimar-Eisenach
{{Flagicon image|Flagge_K%C3%B6nigreich_Sachsen_%281815-1918%29.svg}} Saxony – Kingdom of Saxony
{{Flagicon image|Flagge_F%C3%BCrstentum_Lippe.svg}} Schaumburg-Lippe – Principality of Schaumburg-Lippe
{{Flagicon image|Schleswig Arms.svg}} Schleswig – Duchy of Schleswig
{{Flagicon image|Schwarzburg-Rudolstadt_Flag_1815.png}} Schwarzburg-Rudolstadt – Principality of Schwarzburg-Rudolstadt
{{Flagicon image|Flagge_F%C3%BCrstent%C3%BCmer_Schwarzburg.svg}} Schwarzburg-Sondershausen – Principality of Schwarzburg-Sondershausen
{{Flagicon image|Flag_of_Selangor.svg}} Selangor – Sultanate of Selangor
{{Flagicon image|Civil Flag of Serbia.svg}} Serbia – Principality of Serbia
{{Flag|Thailand|1855|name=Siam}} – Kingdom of Siam
{{noflag}}Sikkim – Chogyalate of Sikkim
{{Flagicon image|Flag of the Sokoto Caliphate.svg}} Sokoto – Sokoto Caliphate
{{flagcountry|South African Republic}} – South African Republic
{{Flag|Spain|1785}} – Kingdom of Spain
{{Flagicon image|18th Century Flag of Sulu.svg}} Sulu – Sultanate of Sulu
{{Flag|Sweden|1844}} – Kingdom of Sweden (in personal union with Norway)
{{Flag|Switzerland}} – Swiss Confederation
T
{{Flagicon image|Flag_of_the_Tahiti_Protectorate_1843-1880.svg}} Tahiti – Kingdom of Tahiti
{{noflag}}Tonga – Tu'i Tonga
{{Flagicon image|Flag of Toro, Uganda.svg}} Toro – Toro Kingdom
{{noflag}}Toucouleur – Toucouleur Empire
{{flag|Two Sicilies|1860}} – Kingdom of the Two Sicilies {{small|(to February 12)}}
U
{{Flagcountry|United Kingdom of Great Britain and Ireland|1801}} – United Kingdom of Great Britain and Ireland
{{Flagdeco|United States|1859}} → {{Flag|United States|1861}} – United States of America
{{flagicon image|Flag of the United States of the Ionian Islands.svg}} United States of the Ionian Islands – United States of the Ionian Islands
{{Flag|Uruguay}} – Eastern Republic of Uruguay
V
{{Flag|Venezuela|1859}} – Republic of Venezuela
W
{{Flagdeco|Germany|Weimar}} Waldeck-Pyrmont – Principality of Waldeck and Pyrmont
{{noflag}}Welayta – Kingdom of Welayta
{{flag|Württemberg}} – Kingdom of Württemberg
Y
{{noflag}}Yeke – Yeke Kingdom
Z
{{Flag|Zanzibar|Sultanate}} – Sultanate of Zanzibar {{small|(from April 6)}}
{{noflag}}Zululand – Kingdom of the Zulus
States claiming sovereignty
{{Flagicon image|Sultanate of Aceh Flag.png}} Aceh – Sultanate of Aceh
{{Flagicon image|Alabama 1861 Obverse.svg|border}} Alabama – Republic of Alabama {{small|(from January 11 to February 4)}}
{{Flagicon image|Flag_of_the_Kingdom_of_Araucanía_and_Patagonia.svg}} Araucania and Patagonia – Kingdom of Araucania and Patagoniato
{{flag|Arkansas}} – Republic of Arkansas {{small|(from May 6 to May 18)}}
{{Flagdeco|Confederate States of America|1861a}} → {{Flagdeco|Confederate States of America|1861b}} → {{Flagdeco|Confederate States of America|1861c}} → {{Flagcountry|Confederate States of America|1861}} – Confederate States of America {{small|(from February 4)}}
{{Flagicon|Florida|1861}} Florida – Republic Florida {{small|(from January 10 to February 4)}}
{{Flagicon|Louisiana|1861}} Louisiana – Republic of Louisiana {{small|(from January 26 to February 4)}}
{{Flagcountry|Republic of Mississippi}} – Republic of Mississippi {{small|(from January 9 to February 8)}}
{{Flag|North Carolina|1861}} {{small|(from May 20 to May 21)}}
{{Flagicon image|Flag of South Carolina (January 1861).svg}} South Carolina – Republic of South Carolina {{small|(to February 8)}}
{{Flagicon image|Flag of Argentina.svg}} State of Buenos Aires {{small|(to December 7)}}
Taiping Heavenly Kingdom - Heavenly Kingdom of Great Peace
{{Flagicon image|Tennessee_1861_proposed.svg}} Tennessee - Republic of Tennessee {{small|(from June 8 to July 2)}}
{{Flag|Texas}} – Republic of Texas {{small|(from February 1 to March 2)}}
{{Flag|Virginia|1861}} – Republic of Virginia {{small|(from April 17 to May 7)}}
{{Lists of sovereign states by year |expanded=CE}}