The incident happened as the girl was on her way to the Gulskogen school in Drammen.
After being hit, the girl returned home and told her parents she was having stomach pains. She was then rushed to a Drammen hospital for a medical examination.
The motorist who struck the girl did not stop but thanks to several witness sightings, police found the car and the driver. The person, whose gender and age was not immediately released, was scheduled for questioning and blood tests for illicit substances later on Wednesday.
Both police and an ambulance crew came to the girl's home when they received notice of what had happened.
“Police thank those who helped the injured girl, and those who contributed with important and good sightings allowing us to find the car,” the South East Police District wrote on Twitter.