NIFRS responded to a road traffic collision involving two cars at Legavallon Road in Dungiven on Saturday.
Firefighters used hydraulic cutting equipment to release a 40-year-old woman from one car.
Two other casualties – a 30-year-old man and a 12-year-old girl – were out of the vehicles on arrival of FRS.
All casualties were taken to hospital by ambulance. Fire crews from Dungiven station attended the incident.