Simplify the following text for a Grade 11 native English-speaking person.
Original: Burgess Hill is predominantly situated just on the West Sussex side of the border dividing the two counties , although parts of the World 's End district in the northeast are across the county boundary in the Lewes district of East Sussex .
Simplified: Burgess Hill is mainly situated just on the West Sussex side of the border dividing the two counties , although parts of the town are across the county boundary in East Sussex .