The effect of the campaign was not completely shrugged off by the Iroquois. In November, almost 3,000 Indians were huddled around the gates of Fort Niagara seeking aid from the British.17 The winter of 1779/1780 was the worst possible time for the Indians to have lost their homes and crops. Five to six feet of snow covered the northeast for weeks. Many climatologists believe a “Little Ice Age” occurred in America from 1750 to 1850. One pointed out that the winter of 1779/80 was the extreme winter of the “cool hundred years”. Many contemporary people referred to it as the “The Hard Winter”. As a result, hundreds of Indians died of disease, exposure, or malnutrition.18
In 1780, the Iroquois resumed their raids on the New York frontier. Fueled by a desire for vengeance stemming from the Sullivan Campaign, the number of raids increased dramatically. In July, Joseph Brant destroyed the Oneida and Tuscarora villages around Oneida Castle. Some 150 Oneidas were forced to go to Fort Niagara, however, over 400 fled to Fort Stanwix. The refugees at Stanwix later migrated to Schenectady, where they were forced to live outside the walls. Like their brothers at Fort Niagara, they suffered greatly from exposure and malnutrition when winter arrived. Many moved north hoping to hunt and survive in the wilderness, but were forced to return when game proved scarce.
Thus, the Indians fared no better than other residents of the valley. Loss of homes and crops left the Indians suffering as much as their white neighbors. At the end of the war, they were to lose something of even greater value – their lands.
The devastation and suffering in the valley were shared by all who lived there. Loyalist, Patriot, Indian – all suffered. Of the estimated10,000 white population in 1777, approximately 1,000 were killed or taken prisoner. Some 2,500 to 3,000 Loyalists left the valley and about 3,000 Patriots abandoned their farms.
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via What Happened to 7,000 People.