Simplify the following text for a Grade 11 native English-speaking person.
Original: Harrisburg is the county seat of Dauphin County and lies on the east bank of the Susquehanna River , 105 miles ( 169 km ) west-northwest of Philadelphia .
Simplified: Harrisburg is the county seat of Dauphin County and is on the Susquehanna River , 105 miles ( 169 km ) northwest of Philadelphia .