The crash occurred in the i100 Block of Hahnstown Road in Ephrata Township around 4:20 p.m.
A tractor-trailer traveling south hit the side mirrors of the bus, which was traveling the opposite direction.
Six children from the Ephrata Area School District were on the bus at the time of the crash, none of them were injured.
The bus driver was injured by "flying glass and debris when the large side mirror swung into and shattered the side bus window," police say.
The driver sustained a head injury and was transported WellSpan Ephrata Hospital.
The status of the driver is unknown.
The tractor-trailer driver, from York, was not injured.
Ephrata Police were assisted on scene by Pioneer Fire Co, Pioneer Fire Police and Ephrata Ambulance and Medic.
An investigation into the crash is ongoing.
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