Virginia is a particular challenge for researchers, not only do a great many of us have ancestors from that area, but Virginia has several counties which are no longer in existence. Those counties are as follow:
Elizabeth City County: This was one of the original first eight counties of Virginia. Formed in 1634 it was previously named Kikotan (or Kecoughtan and Kikowtan). The county disappeared in 1952 when it merged with the city of Hampton.
Fincastle County: created in 1772 from Botetourt County, which, at that time, extended all the way to the Mississippi River. Fincastle's life was short lived, however. It was abolished in 1776 and divided into the counties of Montgomery, Washington, and Kentucky (which later became the state of Kentucky).
Lower Norfolk: This county began in 1637 when it was created from New Norfolk County. Lower Norfolk was renamed in 1691 to Norfolk County and disappeared altogether in 1963 when it became a part of the city of Chesapeake.
Nansemond: Created from Upper Norfolk County in 1646 becoming the City of Nansemond in 1972. In 1974 it merged with the city of Suffolk.
New Norfolk County: Formed in 1636 from the part of Elizabeth City County (formed in 1634) south of the James River. In 1637 it was divided into Upper Norfolk County and Lower Norfolk county. Are you confused yet?
Norfolk County: Created in 1691 from Lower Norfolk County. The county disappeared in 1963 when it consolidated with the city of South Norfolk to become the city of Chesapeake.
Princess Anne County; In existence from 1691 to 1963 when the county became part of the city of Virginia Beach.
Upper Norfolk County: See Nansemond County and New Norfolk County above.
Warwick County: Originally named Warrick River County in 1634. The county became the city of Warwick in 1952 and then in 1958 merged into the City of Newport News.
The Library of Virginia has some holdings available relative to these individual county records. More information can be found at The Library of Virginia.