One of largest rivers in Europe. Known anciently as the Ister. Originates from confluence of two small rivers in Black Forest of southwest Germany, elevation about 2,900 feet, and terminates in Romania and Ukraine in Black Sea by four different outlets. About 1,800 miles long. Drains over 315,000 square miles. Orson Hyde wrote letter from bank of river to report on his missionary travels, 17 July 1841.