In late 1778, General Clinton shipped 3,000 troops from New York to Georgia and launched a Southern invasion against Savannah, reinforced by 2,000 British and Loyalist troops. They repelled an attack by American patriots and French naval forces, which bolstered the British war effort.[197]
In June 1778, Iroquois warriors joined with Loyalist rangers led by Walter Butler and killed more than 200 frontiersmen in June, laying waste to the Wyoming Valley in Pennsylvania.[198] In mid-1779, in response to this and other attacks on New England towns, Washington ordered General John Sullivan to lead an expedition to force the Iroquois out of New York by effecting "the total destruction and devastation" of their villages and by taking their women and children hostage.[199][200] The expedition systematically destroyed Iroquois villages and food stocks, and forced at least 5,036 Iroquois to flee to British Canada. The campaign directly killed a few hundred Iroquois, but according to anthropologist Anthony F. C. Wallace, the net effect of the campaign was to reduce the Iroquois by half, who became unable to support themselves or survive the harsh winter of 1779–1780. 