On the mainland, the governor of Spanish Louisiana, Count Bernardo de Gálvez, led a series of successful offensives against the British forts in the Mississippi Valley, first the attack and capture of Fort Bute at Manchac and then forcing the surrender of Baton Rouge, Natchez and Mobile in 1779 and 1780.Harvey p.413-14 While a hurricane halted an expedition to capture Pensacola, the capital of British West Florida, in 1780, Gálvez's forces achieved a decisive victory against the British in 1781 at the Battle of Pensacola giving the Spanish control of all of West Florida. This secured the southern route for supplies and closed off the possibility of any British offensive into the western frontier of United States via the Mississippi River.
