There is still considerable debate regarding Thomas Jefferson's purported Welsh ancestry. To date, no hard evidence connecting Jefferson's known ancestors to Wales has been found.
"The tradition in my father’s family was that their ancestor came to this country from Wales, and from near the mountain of Snowden, the highest in Gr. Br. I noted once a case from Wales in the law reports where a person of our name was either pl. or def. and one of the same name was Secretary to the Virginia company. these are the only instances in which I have met with the name in that country. I have found it in our early records ...."
Jefferson went on to say that the only "particular information" he had of any paternal ancestor was about his grandfather, also named Thomas (1679-1731). While Jefferson knew little about his father's line, he was well-informed about his mother's people, the Randolphs: "They trace their pedigree far back in England and Scotland, to which let every one ascribe the faith and merit he chooses."
Henry Randall, a nineteenth-century biographer, took the Jefferson line only to Jefferson's grandfather Thomas. Randall mentioned the tradition of emigration from Wales and also noted that a Jefferson was among the Colonial Assembly at Jamestown in 1619. In Sarah Nicholas Randolph's life of her great-grandfather, she included Jefferson's statements from the Autobiography about a Welsh connection. She also cited the Jefferson name among the legislative assembly in Jamestown in 1619, adding that the Jeffersons first arrived in Virginia in 1612. But she had no evidence for a link between the Jamestown Jefferson and Thomas Jefferson's line.
More recently, Dumas Malone took the line back one more generation, to a Thomas Jefferson who was living in Henrico County in 1679. Malone also observed that Jefferson never spent much time on the remote subject of genealogy. Though the Welsh connection remained elusive, Malone noted that Peter Jefferson named his place on the James River "Snowden," after the mountain in Wales where early Jeffersons supposedly lived. Beyond the first Thomas Jefferson (Jefferson's great-grandfather), Malone felt the records were too scanty to draw any conclusions.
Two possible lineages have been presented. In an essay in the Collected Papers of the Monticello Association, Olivia Taylor presented material which places the early Jeffersons in England, not Wales. Beyond the Thomas Jefferson who died in Virginia in 1697 is the Jeaffreson family, a well-documented English line from Samuel Jeaffreson (d. ante October 23, 1590), owner of an estate in Suffolk, to Samuel Jeaffreson (bapt. October 11, 1607 – d. after 1685), a planter in St. Christopher's and Antigua. This Samuel Jeaffreson had three sons, Samuel, Thomas, and Richard. This Thomas may be Jefferson's great-grandfather.
Another lineage has been proposed by Edgar Hickisch in an unpublished monograph on Peter Jefferson. Hickisch cited the work done by Marie Therese Jeaffreson in the British Museum. According to this source, one John Jeaffreson came to Virginia early in the 17th century, made a fortune, and returned to England, where he married Ann Scott and purchased Dullingham House. The coat of arms John Jeaffreson acquired was the same as the one used by Monticello's Thomas Jefferson. Members of this family who emigrated to Virginia, presumably to find fortunes equal to John's, were William in 1650, Mary in 1653, and Thomas, who arrived about 1660. This Thomas might be Jefferson's great-grandfather, but his English origins are still unclear.
Further work needs to be done; evidently, no one has made any efforts in Wales.
- Russell Martin, 2/9/90
931 Thomas Jefferson Parkway
Charlottesville, VA 22902