Schwarzburg-Sondershausen was a small principality in Germany, in the present day state of Thuringia, with capital at Sondershausen.
Schwarzburg-Sondershausen was a county until 1697; in that year it became a principality, which lasted until the fall of the German monarchies in 1918, during the German Revolution of 1918–1919. After the German Revolution, it became a republic.
In 1920 it joined with other small states in the area to form the new state of Thuringia. Schwarzburg-Sondershausen had an area of 862 km² and a population of 85,000 (1905). Towns placed in the state were: Arnstadt, Sondershausen, Gehren, Langewiesen, Großbreitenbach, Ebeleben, Großenehrich, Greußen and Plaue.
Rulers of Schwarzburg-Sondershausen, 1552–1918
Counts of Schwarzburg-Sondershausen
Raised to Principality in 1697
Princes of Schwarzburg-Sondershausen
United under Prince Günther of Schwarzburg-Rudolstadt
Heads of the princely house of Schwarzburg
On the death of the childless Prince Günther Victor in 1925 he was succeeded by Prince Sizzo (1860–1926) who was the son of Prince Friedrich Günther (1793–1867) from his second, morganatic marriage. Prince Sizzo was recognised as a full member of the House of Schwarzburg in 1896. Upon the death of Prince Friedrich Günther, the last in the male line, the headship passed under Semi-Salic primogeniture to his elder sister, Princess Marie Antoinette of Schwarzburg who married Friedrich Magnus V, Count of Solms-Wildenfels. The House of Schwarzburg subsequently became a personal union with the House of Solms-Wildenfels. 
Villages with more than 2000 people
Template:States of the Confederation of the Rhine