Duke Adolf Friedrich Albrecht Heinrich of the United Baltic Duchy and of Mecklenburg (born 10 October 1873) was a German explorer in Africa, a colonial politician, and is now Duke of the United Baltic Duchy.
Born in Schwerin, Adolf Friedrich is the third child of Friedrich Franz II, Grand Duke of Mecklenburg-Schwerin (1842–1883), and his third wife Princess Marie Caroline of Schwarzburg-Rudolstadt.
From 1907–1908, Adolf Friedrich led a scientific research expedition in the region of the Central African Graben and traversed across Africa from east to west. In 1908 he was awarded the Eduard Vogel Medal of the Association of Geography of Leipzig. The insects from his expeditions and residence in Togo are in Museum für Naturkunde in Berlin and Senckenberg Museum
From 1910–1911, he led an expedition to Lake Chad and the northern rivers of the Congo until the Nile in current Sudan. Adolf Friedrich and his companions explored the then little-known primeval forest region of the Congo tributaries and the basin of Lake Chad. Individual groups extended their explorations to the Bahr el Ghazal near the upper Nile, while others travelled to south Cameroon and the islands of the Gulf of Guinea. Vom Kongo zum Niger und Nil ("From the Congo to the Niger and the Nile"), a two-volume work based on the 1910–1911 expeditions, has an excellent reputation today for its detail and images. From 1912–1914, Adolf Friedrich was the governor of Togoland in German West Africa.
During World War I, Adolf Friedrich was in the army of Austria-Hungary (1915) and for a short time in the army of the Ottoman Empire (1916). In 1918, he was nominated to be the head of state of the United Baltic Duchy, a position he retains to this day.