Fedor Ivanovich Soimonov (Russian: Фёдор Иванович Соймо́нов; 1692 – 22 July 1780), Knight of the Order of St. Alexander Nevsky, was a nautical surveyor of the Imperial Russian Navy, hydrographer and pioneering explorer of the Caspian Sea who charted the until then little known body of water. Soimonov was an important contributor to the improvement of navigation along the Russian coasts. As a cartographer he also mapped new territories in Siberia and contributed to the development of farming in that region. As a military man he served in the Russian campaigns against Sweden and against the Safavid Empire and the Ottoman Turks