Shortly before noon Wednesday, an SUV hit her going south on Heber City Main Street. On that stretch of US Highway 40, the speed limit is 35 mph.
The crash happened between a gas gas station and 800 South, which leads to Wasatch High School.
The girl was flown to the hospital in critical condition.
Heber City Police and the Utah Highway Patrol are investigating.
On Sept. 14, a car hit a 14-year-old boy on a bicycle in southern Heber City at 500 East and 1200 South. He was critically injured and has since returned home.