It happened around 2 p.m. Saturday at the Yogi Bear's Jellystone Park in Alloway Township.
Police say the girl was in her tent with others when she was struck by the branch.
She was transported to an area hospital, where was pronounced dead a short time later.
Strong storms were passing through the state on that day, but it's unclear whether the weather played a part in the accident.
No other injuries were reported in the accident.
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