We do not know precisely when Nancy died. She is living with son Richard at the 1870 census (Clay). She is a widow living with daughter Sally at the 1880 census (Leslie). A series of deeds transferring the property of Simeon Wilson appear starting 1884 in Harlan and Leslie County. It seems likely that the property remained in Nancy's hands until her death placing her death about 1882 or 1883.
Nancy's family pronounced her name Woloford. The death certificate for a couple of her children has that. This researcher's grandmother pronounced her name Woloford. (She was born 1867, grew up just down Beech Fork from Nancy, must have known her, but she never spoke of her grandmother except to give her name). BUT the close proximity of John Williford is too convincing to ignore. DNA supports the thesis that she was a Williford.
    John Williford 1st appears on Knox tax list 1804, Richard Wilson 1806. John Williford last appears on a Harlan tax list in 1827. 1828-1832 tax list have not survived. He is in the 1830 census. No Williford appears on the 1833 tax list (but neither does Simeon & Isaiah Wilson, John & Richard Wilson do). Elizabeth Williford replaces John on the 1834 tax list; John Williford estate appears in 1835; Elizabeth Williford appears again in 1836. No Willifords after that. You have to believe Elizabeth was his widow and presumably Nancy's mother (Sim & Nancy's first child was Elizabeth.)
Harlan Court Orders
May Term 1831
On the motion of Elisha Green, it is ordered that Frederick Miracle, Jospeh Wilder, James Green, Nelson Salyers, John Williford, and Jolies Cox be appointed to view a road from William Green's to intersect the state road near Robert George's or David Hogan's.

November Term 1836 page 330
This day Elisha Green and John Jones Sr produced the last will and testament of John Wiliford decd and proved by the oath of Larkin Howard one of the subscribing witnesses. Whereupon the said Elisha Green one of the executors mentioned on said will executed bond for the penal sum of eight hundred dollars with William Green his security conditioned as the law directs. Whereupon the said Elisha Green had the necessary oath sworn and on the motion of Elisha Green: John McGeorge, Larkin Howard and Abraham Slusher are appointed appropriate to appraise the property of John Williford deceased and to report to the court as the law directs

John Williford was b 1766-1770 d 1831-1834 wife (Elizabeth) was born 1761-1765

1810 Knox
1 m 16-25 unknown (b1784-1794) likely Peter
1 m 26-44 himself
1 f under 10 Fanny ?
2 f 10-15 Nancy age 13 and one other (possibly Betsy)
1 f 16-26 unknown b 1784-94 possibly daughter-in-law or possibly the Betsy who married James Garrard or Garrard James (that Betsy could be Peter's widow)
1 f over 45 wife

1820 Harlan
1 m under 10 Washington b 1818 ?
1 m over 45 himself
2 f under 10 unknown one may be granddau Betsy Chappell
1 f 16-26 Nancy age 23 (Sim is alone next house) where is Fannie ? age 10-20
1 f over 45 wife

1830 Harlan
1 m 1-4 unknown likely grandchild
1 m 10-14 Washington age 12 ?
1 m 60-69 himself b 1761-1770
1 f 1-4 must be granddau possibly Isaiah's & Fanny's dau Nancy b 2-4-1824
1 f 5-9 must be granddau possibly Isaiah's & Fanny's dau Esther b 8-19-1826
1 f 20-29 possibly Fanny b 1801-1810
1 f 60-69 wife (given her age it's unlikely John was married multiple times)

We do have some clues to the other children, but they are very nebulous. He may also have had children that never moved to KY (perhaps the John of 1790).
1. There was a Peter Williford in early Harlan, possibly John's son. Peter Williford was a private in Capt Ambrose Arthur's company War of 1812. Arthur's company was part of Dudley's regiment and they are known for Dudley's Defeat where about 3/4 of the regiment was killed by (mostly) Indians May 5, 1813 when they carelessly pursued the Indians. There is a high probability that Peter was one of those killed. 846 men in regiment, 170 escaped, rest were killed, captured or missing. There is a listing of about 170 of the casualties (he not among them). The bodies that were recovered are buried in a mass grave on 'Kentucky Hill' at the site of Fort Meigs (now a state park at Perrysburg, OH). There is no marker of any kind. Surely the same Peter mentioned in a Harlan deed 1830 Wm Taylor & Catherine Saylor including an improvement made by Petter Williford.
2. Knox marriages - Betsy Wilford to Garrard James 8-24-1816 Typewritten index at clerks office give groom as Garrard James. Some transcriptions give groom as James Garrard (James connection to the prominent Clay and Bourbon County Garrard family is unknown). Betsy may be Nancy's sister or, more likely, she was Peter's widow.
3. Simeon's brother Isaiah had two children, Nancy and Esther 1824 and 1826, with someone named Fannie. We know this because Fannie bound these children out (as Fannie Wilson) and then Isaiah claimed them (reference to Fannie Stapleton). Nancy is Williford in 1850 census. That means she either married a Williford or used her mother's name of Williford. Very possibly Fannie is Nancy's sister who eventually married a Stapleton.
4. Not exactly relevant, but Washington Williford has to be Nancy's nephew.
January Term 1837 Harlan County Court
This day Washington Williford an infant eighteen years old on the 20th of last Feb came into court and cose (Chose?) James Sparks as his guardian. Whereupon came the said James Sparks together with Henry Morris(?) his security and executed bond to the commonwealth in $500 conditioned as the law directs.

(these 2 deeds are probably the same, one is a mistranscription of the year)
Deed Book D page 63 Washingron Wilosford sold property in Harlan County to Wm S Howard 9-25-1843
Deed Book D, page 63, Indenture from Washington Wilasford to William S Howard, 25
September 1848, bounding Zachariah Saylor's part of land sold by John Hendrickson to John
Willesford; witnesses not listed

John Carl Wilson reports that Washington Williford sold property on Pucketts Creek to William S. Howard in 1846 (is this a different transaction?)

The close proximity of the John and Washington Williford properties speaks volumes about their relationship.Likely he was one of those younger children in John's 1820 and 1830 households, then needed a guardian after Elizabeth's death. Doesn't say anything about his parents (probably wasn't Peter).
The census implies that Simeon and Nancy were married after the 1820 census because Simeon is alone at that census and there is a girl in the John Williford household next door of the right age to be Nancy . However, the birth date of their oldest child , Betsy Chappell, as given on her tombstone (9-18-1819) would imply that they should have been married no later than January 1819. In any case, they were likely married about the time Harlan was formed out of Knox and they could easily have been married in either county. No marriage record for them survives in either county. They did live in the most southeastern corner of the state at that time, not more than 5 miles from either Lee County, VA or Claiborne County, TN (perhaps 20 miles from the county seat of either). The earliest surviving marriage records for both those counties are from the 1830s. Most likely they were married Knox or Harlan and the record is simply lost. There are rumors of the Knox County Clerk dumping a truckload of records in the mid 20th century. Some Harlan records are lost, for example: the 1827 Harlan marriage of John Muncy and Elizabeth Templeton is not among the surviving records, yet his pension file has two copies of the bond dating to the 1850s..
The precise origin of Felix Lewis 'testimony' is unknown to this researcher, but it bears the mark of Annie Walker Burns. She solicited statements in the 1930s from several old timers in Harlan and surrounding counties. She refers to those statements as their 'testimony'. Felix 's statement is the closest thing we have to a statement from Simeon and Nancy themselves. Felix was one of their older grandchildren (though far from the oldest) and would be in a position to know. His statement:
My father married a Wilson, her name was Clarenda Wilson, my grandfather was named Limuel Wilson. Grandmother was named Nancy, He came from North Carolina and she came from the Purchase in Tennessee, the Indian Purchase, the Cherokee. She could talk the Indian language, I was small then and I don't remember much about it, she was reared right among the Indians in the Purchase. I don't know what the name of the county in Tenn. was. I remember when young, she said the Indian were the best friends in the world, but if you ever deceive an Indian he would never have anything to do with you. I remember what she said, she said when you traded with them and when you did not give them good weight, they would say stingy. Henry M Lewis made a will to his wife Clarinda Wilson 1875 and children: Wilson Lewis, Hampton Lewis, Cath. Wells, late Cath. Lewis and Felix Lewis and John C Lewis, who lives in Va. and Martha and Henry who were heirs of John C. Lewis.
Some descendants claim Nancy had Indian blood and this statement is probably the origin of that. This statement really implies otherwise. More likely, her father was a trader among the Cherokee or a squatter on their land. Note that he says she came from TN, not that she was born there (she consistently tells the census taker she was born in SC). The Spartanburg area of SC is very close to TN and it's easy to believe the family moved a few miles into TN. Note that Nancy was only 7 years old when John Williford appears in KY.
    There's also a James Williford (1781-1849) in early Clay County. He also has a girl in his household of the right age to be Nancy, but he's somewhat distant. This entire family moved in 1834 to Henry County, Iowa (then Wisconsin Territory) and are well documented there. This appears to be the same James that was a son of Samuel Williford of Madison County, KY.
       There are two Williford books: 'Wilford-Williford Treks in America' by Eurie Pearl Wilford Neel 1959, 1050 pages (289 pages Williford family, 147 pages allied families, 613 pages are a reprint of Perrin's History of KY as it relates to Trigg & Christian Counties). There are numerous references to the Trek of some Willifords from coastal Bertie County NC to first Spartanburg, SC, then Wilson and Muary Counties TN, then to extreme western KY (Jackson Purchase) - Trigg, Calloway and Graves Counties. Nancy Williford consistently told the census taker she was born SC. This is consistent with her being part of this group of Willifords. The second Williford book is 'Williford and Allied Families' by William Bailey Williford 1961. The second book is narrowly focused on the authors ancestors and conflicts with the first on an important point. The Willifords of Bertie County were major slaveholders and the elements that migrated to western KY were also.
     The earliest Willifords in America (1st 3 generations) are well established (they left a trail of estate documents). Beyond that it gets murky, particularly as it relates to John Williford of Harlan!
Thomas Williford died circa 1676, one of 23 hanged for participation in Bacon's Rebellion against Governor William Berkley of Virginia; second son of a knight (the lowest rank of English nobility), Sir Thomas Wilsford. As a second son he did not inherit his father's property or titles.
His only known child was John born circa 1670 m Jane, lived Isle of Wight County, VA
    a. Wm 1693 moved across the Chowan River to Bertie County, NC by 1726
         a1.Samuel
         a2. William Jr to Granville, then Duplin, then Sampson Counties , NC
         a3. Constable
         a4. James
    b. Mary 1695
    c. John Jr 1699 d 1761 m Mary,3 lived in portion of Isle of Wight County that became Southhampton; children named in estate
d. Richard 1701 moved across Chowan River to Bertie County, NC by 1717 (when still a part of Albermarle County) d 1766 m Abigail
         d1 Richard Jr.
         d2 Benton
         d3 John 
The children of c John Jr 1699 as named in estate (except as noted) are:
1. Nathan 1720 moved to Warren County, NC 1771 d 1-1780; children named in will
    1a. Samuel moved to Madison County, KY after 1790 according to 'Treks' , but the second book claims him as the author's ancestor and says he lived in GA. Likely, one of the Samuels was a1, the son of William.
    1b. Dorender West
    1c. Britton b 5-20-1742 d 10-1836 Giles County, TN; RW Vet; Spartanburg 1790; to Giles CountyTN 1818. By all accounts he married Lucy Lancaster. These 3 children are well documented:
          1c1 Willis b 6-14-1773 d 7-6-1854;m1 Elizabeth Williams in Wilson County, NC m2 Rebecca Ann Batts 9-26-1839 Henry County, TN; lived Calloway County, KY; found 1820 Maury County, TN His death record gives hsi parents as Britton Williford and Lucy. 
          1c2 William aka Wiley bc 1775  lived Maury County, TN; found 1800, 1810 Spartanburg, SC, 1820 Giles County,TN                                                            
          1c3 Hardy b 1-18-1785 d 7-9-1869 m Nancy Compton; lived Giles County. TN, found 1810 Spartanburg. SC, 1820 Giles, TN; buried Mt Ararat Cemetery, Lawrence County, TN
     1d. Susana Lancaster
     1e. Sarah Lancaster
     1f. Mary m1 Josiah Green 5-10-1773 Bute County NC m2 Isom Green 4-23-1777
     1g. Nathan Jr b 9-15-1757 moved to 96 District, SC by 1779; Ensign NC militia, fought at Kings Mtn and Cowpens ; in Elbert County, GA 1801; applied fro RW pension 3-4-1831 GA; died 1-3-1842 GA; found Cherokee County, NC 1840 age 80-90
 2. Thomas (executor) bc 1729 to Edgecombe County by 2-21-1765 one Thomas found 1790. 1800 Edgecombe
     2a. Hartwell 1749 found 1790 Edgecombe, NC, Warren County, GA 1800
     2b. Benjamin 1751 found Edgecombe County, NC 1800
     2c. Joseph 1753
     2d. Jacob 1755 found Edgecombe County, NC 1790 & 1800; found Grainger County, TN 1830 age 70-80 along with James & Simeon; applied fro RW Pension 3-4-1831 TN; died 2-18-1839 TN
     2e. John 1757 one John found Edgecombe County, NC 1790 & 1800
     2f. James 1759
     2g. Willis 1761  
3. John III b ? d 1746 – 'Treks' lists him as a child. He is not listed in the estate because he died fifteen years before his father. Many online pedigrees give his burth year as 1631 and say he is the father of Theophilus (and perhaps by implication the John Williford of Harlan County, KY.), but if he were born 1631 he died at age 15 (with a wife and children ?) and he died before Theophilus was born and about 20 years before the John of Harlan.
4. Wm m Mary Johnson d before 9-15-1783 Southhampton County, VA; children named in will
     4a. Belah (male) m Patience Brock, one Bela Williford was a privateVA Militia War of 1812
     4b. Jordan b 5-30-1759, one Jordan Williford was in VA Militia War of 1812
     4c. Jeremiah
     4d Johnson
     4e. James
     4f. Sally m Sion Fuller11-11-1799 Southhampton County
     4g. Mary
5. Elizabeth Jones
6. Mary Boasman
7. Lucy
8 Mourning

John Carl Wilson has access to the DNA test results of several descendants of Nancy and Simeon as well as some other Willifords and intersecting families. .He has done extensive comparison and analysis on that data using a variety of tools and techniques. From his analysis we can conclude Nancy Williford Wilson is closely related to 6 other Willifords (more distantly to several others):
1. Britton Williford b 5-20-1742 d 10-1836 Giles County, TN; RW Vet; found Spartanburg 1790-1810; to Giles County 1818. His 1790 household has 2 males under 16 (Wyley age 15 and Hardy age 5) and 3 over 16 (himself, Willis 17 and likely John of Harlan age 20-25), 1 female (wife Lucy Lancaster).
2. Willis Williford b 6-14-1773 d 7-6-1854;m1 Elizabeth Williams in Wilson County, NC m2 Rebecca Ann Batts 9-26-1839 Henry County, TN; lived Calloway County, KY; found 1820 Maury County, TN His death record gives his parents as Britton Williford and Lucy.  He is a very strong match.
3.Wiley Williford bc 1775 lived Maury County, TN; found 1800, 1810 Spartanburg, SC, 1820 Giles County, TN. Another son of Britton.                                                            
4. Hardy Williford b 1-18-1785 d 7-9-1869 m Nancy Compton (daughter of Basil Compton and Sarah Winn Bearden). Another son of Britton; lived Giles County. TN, found 1810 Spartanburg. SC, 1820 Giles, TN; buried Mt Ararat Cemetery, Lawrence County, TN. Nancy (8-28-1798 to 7-17-1878) is buried John Laird Cemetery, Giles County, TN. This Nancy has been confused by a ton of people on Ancestry with Simeon Wilson's wife Nancy Williford.
5. Theophilus Williford b 1755-1764 m 1 ? m2 Sally Gwin 5-24-1787 Warren County, NC m3 Elizabeth Arnold 10-25-1800 Pearson county, NC. Found 1786 Warren County, NC, 1790 census Lincoln County, NC, 1793 Pearson County, NC. According to some accounts he died d after 1803 Ogelthorpe County, GA (Madison County since 1812). Other researchers say he did not die circa 1803 GA and is found 1806 in Sumter County, TN (north of Nashville, adjoins Allen and Simpson, KY) and they list his children.
6. John Williford b 1790 KY or TN ended up in AR
Also, some descendants of Simeon and Nancy match the descendants of Lawrence Lancaster (1712-1792) and Mary Williams (1716-1762).
    DNA has limits. It can't tell you with any precision the relationships among these people. However, looking at what we know of the family, their relative ages, and DNA evidence, you can confidently conclude that John Williford of Harlan is the second son of Britton Williford (1742-1836) who married Lucy, making this John the grandson of Nathan Williford, great grandson of John Williford II 1699. Further, you can conclude with confidence that Theophilus is the brother of John of Harlan and the younger John 1790 is the son of one of those brothers. Note that Britton wrote a will in 1829 Gibson County, TN, during John Williford's lifetime and John is not mentioned in the will, but there is no requirement that he would be. .
Numerous descendants of Simeon and Nancy are DNA matches to the descendants of John William Bearden (1717-1797) and Lettice Caty Winn (1723-1797 daughter of Minor Winn and Margaret O'Conner). Descendants of Washington Williford also match this family and have no connection to Simeon. Thus you can conclude John Williford's wife, Elizabeth (Nancy's mother) is a descendant of John William Bearden and Lettice. Simeon and Nancy's descendant also match members of the Langston family. John Willifords's wife (Nancy Williford Wilson's mother), Elizabeth, was surely a Bearden or Winn or a Langston, likely all three. X-Dna analysis suggests she is the daughter ofJohn & Lettice's son John Jr. who married Nancy Ann Langston (they were known to have a daughter Elizabeth). Their daughter Sarah married Basil Compton and Basil's daughter Nancy married Hardy Williford, probably making the two Nancys first cousins.)