The victim, India Mevhue was enjoying a horse ride along with her family members in the hill station on Tuesday evening when suddenly the animal went wild, Matheran police station sub-inspector Rajvardhan Khebude said.
The girl lost her balance and fell from the galloping horse and got dragged nearly 300 ft, he said.
In the mishap, the girl sustained head injury. She was rushed to a local government hospital where doctors declared her brought dead, police said.
The girl along with her family, including her father Govin Mark Mevhue, a British national working with a company in Dubai had come to Matheran from Mumbai for a visit when the mishap occurred.
The girl's parents did not file a complaint against the horse operator, Khebude said adding that the Matheran police have registered a case of accidental death.