At 8 p.m., the girl was trick or treating on North Union Street with her parents when she walked up a flight of steps to a house for candy, when her costume made contact with a lit candle lining the steps and caught on fire, Lambertville police said.
A resident, who was also trick or treating with their child, saw what was happening and patted out the flames with hands, police said.
The child was attended to by neighbors and the homeowner until officers arrived, along with firefighters and the ambulance squad, police said.
The victim sustained first and second-degree burns and was transported to a trauma center for evaluation and treatment. She was later released and expected to recover fully.
The Good Samaritan sustained minor burn injuries to his hands but further treatment, police said.
Click here to follow Daily Voice Flemington-Raritan and receive free news updates.