Question

What militia group prevented general burgoynes army from capturing supplies from an American supply base at bennington,Vermont

Answer 1

The militia group that prevented general Burgoyne's army from capturing supplies from an American supply base at Bennington, Vermont is :
The Green Mountain Boys
They later captured Fort Ticonderoga, which was the first victory for American army in the war

hope this helps

Answer 2

The militias that prevented it were the Green Mountain Boys were a Vermont military unit.

In Greening's Battle of Bennington, the Green Mountain Boys helped US forces defeat an army detachment of British General John Burgoyne led by Lieutenant Colonel Friedrich Baum.