The Principality of Nassau-Usingen was a small German principality located in the region of Hesse-Nassau. Established in the early 19th century, it was part of the larger Nassau territory and was known for its picturesque landscapes and modest population. The principality was ruled by the House of Nassau, which played a significant role in the political landscape of the region. In 1866, the Principality of Nassau-Usingen was dissolved following the Austro-Prussian War, leading to its incorporation into the Prussian province of Hesse-Nassau. Despite its short existence, the principality contributed to the cultural and historical heritage of the area, leaving behind a legacy that is still recognized today.