The following is possibly Joseph's son, but has not been proven (or disproven, for that matter).  The evidence is entirely circumstantial and not convincing — it's my own  family's legend that is probably untrue:
3.  Isaac DAVIS, b. 1760-65 
What is true, and what no doubt led to the birth of our family legend, is that this Isaac DAVIS and his family lived from ca. 1797 to 1818 in the watershed of the West Fork of the Red River, near Fairview, Christian [now Todd] Co., KY, birthplace of Jefferson DAVIS in 1807/8.  The legend is reinforced by the fact that Isaac and his wife's kin had come to the West Fork region from Broad River, in South Carolina, the last certainly known location of Joseph DAVIS.

See page for Joseph DAVIS of Philadelphia and Broad River for the beginning of this commentary.

Joseph DAVIS, son of Evan DAVIS, Sr., signed an indenture in 1762 in Philadelphia as being "of Broad River, South Carolina."  There is a Joseph DAVIS in the Broad River region of NC/SC, namely, our subject, who deserves some investigation as to whether he is Evan's son.

Below is a timeline (extracted from a larger timeline constructed for a different purpose) of events surrounding a Joseph DAVIS in the Broad River regions of NC/SC .  I have included in the timeline individuals in that region known to have moved to Christian/Todd Co., KY, in the late 1790s.  The CLARKs, KUYKENDALLs, WYATTs, FRENCHes, WHITESIDEs, and DAVISes settled in the "West Fork Region" of the Red River watershed in what is now mostly Todd, partly Christian, County, that is, in the region of Fairview, birthplace of Jefferson DAVIS, President CSA. 

My family — like many a southern family with DAVIS ancestors — has a tradition of being cousins to Jefferson DAVIS.  Most of these traditions are untrue, many without the remotest foundation (e.g., see these bogus ancestries of Jefferson DAVIS).  And I should precede my comments with the disclaimer that I am, by nature, a skeptic, and I won't believe any family legend until it is proven true — I've just seen too many proven untrue when exposed to scrutiny.

Our DAVISes were living in the West Fork Region of Christian [now Todd] Co., KY, near Fairview, from the late 1790s until 1818 — the same time period when Samuel DAVIS, father of Jefferson, lived in the region — so I don't think my family can be faulted for having accepted such a tradition for generations.  I do not want to believe it if it isn't true, however, so my starting position is that it is not.  The evidence must convince me otherwise and, as it stands, there appears to be only one possible avenue open to us as a connection and that is through Joseph DAVIS of Broad River, South Carolina. 

And, of course, Y-DNA testing could support/debunk these paper connections, once and for all, if only we could find a proven descendant of Evan DAVIS to be tested. 

(Please see Jefferson Davis Home Page for a general discussion of the possibilies for connection to the late CSA President.) 

1.  Paul R. Sarrett, Jr., compiler. [nd] Some "Early" South Carolina Marriage Records: 1641-1799 (online in the SCGenWeb Archives; file: sc-g1800.txt).

2.  Kirk Bentley Barb.  1971.  "Extract from Genealogy of Jefferson Davis."  Appendix III, pp. 488-508 in Papers of Jefferson Davis, Volume 1, 1808-1840.  Haskell M. Monroe, Jr., and James T. McIntosh, eds.  Louisiana State Univ. Press, Baton Rouge.  [Rev. ed. of 1991 not seen.] 

3.  Will of Evan Davis, Sr., 1743, in which he names his wife and children. 

4.  Indenture, 1762, in which William Davis buys out his siblings' interest in real estate bequeathed to them by their parents.  This document tells us that, at the time, Joseph Davis, carpenter, was "of Broad River in the Colony of South Carolina" and that he came to Philadelphia to be present at the settlement. 

5.  Haskell M. Monroe., Jr. & James T. McIntosh, eds.  1971.  "Genealogy of the Davis Family."  Appendix IV, pp. 505-529 in Papers of Jefferson Davis, Volume 1, 1808-1840.  Louisiana State Univ. Press, Baton Rouge.  [Rev. ed. of 1991 not seen.]

6.  Ernesto Caldeira.  1983.  "Davis Family Genealogy."  Appendix II, pp. 402-416 in Papers of Jefferson Davis, Volume 4, 1849-1852.  Linda Lasswell Christ, Mary Seaton Dix, and Richard E. Beringer, eds.  Louisiana State Univ. Press, Baton Rouge.