There are two distinct families with the last name of Hardin, who settled in what is now Polk and Liberty counties of Texas, during the Republic of Texas era (1836 - 1846).
The first family is that headed by Swan Hardin & Jerusha Blackburn. The prominent sons of this family were (1) Benjamin Watson Hardin (2)Augustine Blackburn Hardin (3)Judge William Hardin (4) Benjamin Franklin 'Frank' Hardin and (5)Milton Ashley Hardin.
The second family was headed by Benjamin Hardin II and Martha Ann 'Patsy' Barnett. Prominent children of this marriage were (1)William Barnett Hardin (2) Joseph Gibson Hardin (father of John Wesley Hardin) (3)Martha Balch Hardin (mother of Mannen Clements) (4)Robert Echison Hardin (5)Benjamin P Hardin (6)Mary Easter Hardin and 5 other children.
Benjamin Hardin II was the son of Col. Joseph Hardin, who Hardin County, Tennessee is named after and Jane Gibson.
Swan Hardin was the son of William Everett Hardin and Sarah Bledsoe of Georgia.
The two Hardin families of Polk and Liberty Counties, Texas are distantly related. Both Benjamin Hardin II (1780 - 1845 Polk Co, TX) and Swan Hardin (1773 - 1829 Liberty Co, TX) are the GG grandsons of Martin Hardin (1650 France - 1706 Virginia) and Madeleine DuSauchoy (1656 - 1735).
There are reliable historical records of both of these Hardin clans in the custody of State of Texas archives, as well as Polk and Liberty Co archives.
As far as is known, there are no inter-marriages between the two Hardin clans of Polk/Liberty Counties.