Overhill was a small village in the Westfarthing, to the north of Hobbiton and The Hill, marking the end of the short road that ran past Bag End and Bagshot Row. Though the Boffin Family was generally associated with The Yale in the Eastfarthing of the Shire, there was at least one Boffin who lived in Overhill: an apparently well-to-do Hobbit who employed Sam's cousin Halfast.
Other Versions of the Legendarium
On the original map of the Shire, Overhill was named "Northope".
