George Clark led a western campaign trying to recruit Natives. He knew the Midwest west from being a surveyor in the Ohio and Kentucky rivers and created his army. He targeted trading villages. They took Kaskaskia and Cahokia. Clark then surprise-attacked Fort Sackville near Vincennes. Wabash was icy and flooded so no one expected it, but Clark's men marched for 18 days through freezing water, bringing many Patriot flags. Sackville surrendered.