Sussex County was created in 1682 from Deale County.
Birth records from 1913 to 1948, marriage records from 1913 to 1980, and death records from 1913 to 1970 can be obtained from the Delaware Public Archives. Birth records from 1942 to the present, marriage records from 1974 to the present, and death records from 1974 to the present can be obtained from the Delaware Office of Vital Statistics.
The Sussex County Recorder of Deeds has land records starting in 1693.
The Sussex County Register of Wills has probate records starting in 1683.
Online indexes and images of some of the above records can be found by using the links on this site.