In the collection of family sketches done by E. B. Hagans, "Hagans" 1769 to 1887 (p. 1), his spouse's surname is mentioned as being Campbell but this text does not include the name John Hagans. This reference was my initial and only source of information about this individual for several years. In 2004, a Hagen Family researcher, William Lon Hagan, had contacted me with a lot of information about another Hagan family branch (Hugh Hagans) which I had no information on, and suggested his branch was connected to the one which I was researching. It took me some time to accept this connection, but Mr. Hagen eventually sent me enough information to convince me that this John Hagans was the connecting point.

From Mr. Hagan (email 28Nov2009):

John HAGANS¹ died about 1806 in Barren Co., KY.
WILL: -- Barren Co. KY Will Book 1 p 56 ~ J. Hagans Will
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Barren County Will Book 1 1800- (http://www.barrencoky.com/Wills/Wills1800-18.htm)
John Haggins, one dollar; Agness Findley, one dollar; .. land ... Boyd and George Findley to be sold... ... Exe.; Witnesses: James Findley and George Findley...
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From Families of Early Jessamine County, Kentucky:

In the name of God Amen. And in the year of our Lord God one thousand eight hundred and six
I John Higgins husbandman of the county of Barren, state of Kentucky, being in a low state of health but of perfect mind and memory, thanks be given to God, therefore and calling to mind the mortality of my body and knowing that it is appointed for all to die, do make and ordain this as my last will and testament, viz first and principally of all I give and recommend my soul into the hands of God that gave it and
my body to the earth to be buried in a Christian like and decent manner at the discretion of my executors to be hereafter mentioned and as touching such worldly estate as it hath pleased God to bless me with this life I devise and bequeath in the manner and form following, viz Imprimis
I do give devise and bequeath unto my truly and well beloved wife Elizabeth Higgins one bed and clothing with the household furniture to be at her disposal, also two milk cows and a year old steer, also one third of what remains of my estate not hereafter bequeathed.
Item I give, devise and bequeath unto my Eldest son Hugh Higgins one dollar.
Item I do give devise and bequeath unto my daughter Mary King one dollar.
Item I do give devise and bequeath unto Margret Wright one dollar.
Item I do give devise and bequeath unto Isable Boyd one dollar.
Item I do give devise and bequeath to Eleanor Higgins one cow and calf.
Item I do give devise and bequeath to Elizabeth McCulloch one dollar.
Item I do give devise and bequeath unto William Hoggins one dollar.
Item I do give devise and bequeath unto Samuel Haggins my house Bible & burket [?]one the new Testament.
Item I do give devise and bequeath unto John Hoggans two cows which he owed by contract and my saddle.
Item I do give devise and bequeath unto Agness Findly one dollar.
It is further my will and pleasure that one hundred acres of wood land lying on the ridge between Samuel Boyd and George Findly be sold by my executors and the money arising there from to pay the former legacies and the remainder together with the debts due to me, a third to my wife as before mentioned, the other two parts to my daughter Eleanor Haggins and I do by these presents nominate constitue [sic] and appoint as executors of this my last will and testament my trusty and well beloved sons William and Samuel Haggans disallowing of all others at any time heretofore met...
and I do by these presents utterly disallow disanul [sic] and revoke all other wills or legacies by me formerly made other [sic] by work of mouth or writing ratifying and confirming this and this only as my last will and testament. In witness whereof hereunto set my hand and seal this 11th of April one thousand eight hundred and six.
N. B. the words Haggans six lines above entered before signed.
Signed, sealed and delivered as my last will and testament in the
presence of the subscribing witnesses James Findley, George Findley
John [his mark] Haggins (SEAL)
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Barren County. To wit October County Court 1806
The foregoing writing purporting to be the last will of John Hogins deceased was produced in court and George Finley one of the subscribing witnesses being sworn deposeth that the said John Haggans did in his presence deliver the said writing as his last will & that he believe him to be in his proper sense & memory when he did it & again at a court held for said county the 17th day November & year aforesaid, James Finly the other subscribing witness being sworn deposeth that the said John Haggins did in his presence deliver the said writing as his will and that he believes he was in his proper sense when he did the same & thereupon the said writing was ordered to be recorded as the true last will & testament of the said John Haggins Dec'd.