Younsmere Hundred was an administrative unit in the Rape of Lewes in the eastern division of the county of Sussex, England until the abolition of hundreds in the 19th century. The Rape was a county sub-division peculiar to Sussex. For most of the Younsmere hundred's existence it included the parishes of Rottingdean (including the detached Balsdean chapelry), Ovingdean and Falmer (including Balmer), i.e. the parishes covering a block of downland east of Brighton.