The Mississippi River is Louisiana's most prominent natural feature, and the high bank or levee at Donaldsonville protects the town from flooding at a site between two great river bends. Events here have long shaped United States history: the first ocean-going ship passed in 1542, though native peoples had lived here thousands of years earlier, and Bayou Lafourche formed a historic connection at the place French explorers in the late 1600s called La Fourche, "the fork," where a major bayou branched from the river and where Donaldsonville was later founded in 1806. Before the Civil War, sugar plantations lined the riverbanks, and with no highways or railways, owners depended on river access to move crops, goods, and passengers; a ferry crossed here, and the mouth of Bayou Lafourche provided another natural route to the Gulf of Mexico. By the early 1900s, vessels of all sizes, including scheduled passenger lines, docked along the shoreline. During the 1860s, Union gunboats tied up here and destroyed a dock used by Confederates to fire on U.S. naval vessels, and in the summer of 1862 Admiral David G. Farragut, aboard the U.S.S. Hartford, warned Donaldsonville's citizens that each attack on his boats would bring the burning of part of their town. In August 1862, Union gunboats shelled Donaldsonville in retaliation for hostile fire from Confederate guerillas in town, and much of the town was destroyed.