Named in honor of the monarch, who was then also Duke of Brunswick-Lüneburg, Lunenburg County was established in 1759, when peninsular Nova Scotia was divided into five counties. Three years later Lunenburg County was reduced in size when Queens County was established. Following the establishment of Queens County in 1762, Hants County in 1781, and Shelburne and Sydney Counties in 1784, the boundaries of all nine of the counties were defined by the Council of Nova Scotia.
By Chapter 52 of the Statutes of 1863 the Township of Chester in the County of Lunenburg was made a separate District for certain specified purposes. That Statute provided authority for the appointment of a Custos Rotulorum and for the establishment of a general sessions of the peace for the District of Chester, with the same powers as if it were a separate county.