Augustine Blackburn Hardin, early settler and signer of the Texas Declaration of Independence, second son of Swan and Jerusha (Blackburn) Hardin, was born in Franklin County, Georgia, on July 18, 1797. By 1807 the family moved to Maury County, Tennessee, where Augustine married Mary Elizabeth Garner in 1819; they had a son. Hardin was deputy sheriff and constable while his father served as justice of the peace in 1825. Augustine Hardin's wife had an affair with Isaac Newton Porter, of which Porter bragged publicly. Augustine and his brothers met Porter and William Williamson in Columbia on October 1, 1825; during the confrontation that followed, Augustine fatally shot Porter, and his brother Benjamin Franklin Hardin killed Williamson. In order to avoid arrest and possible conviction, Augustine, after returning his unfaithful wife and son to her family, left for Texas. He arrived at Nacogdoches in the fall of 1825 and settled on the Trinity River in what is now Liberty County before being indicted for murder on December 21, 1825. Other Hardin family members arrived in Texas by the end of 1828, and no extradition occurred, despite requests from the United States. Augustine Hardin received his land grant in 1831.
On January 16, 1827, he enlisted in a volunteer company organized by Hugh Blair Johnston. The unit marched to Nacogdoches to help quell the Fredonian Rebellion. Hardin represented the Liberty District at the Consultation in 1835 at Columbia and San Felipe de Austin, and again at the Convention of 1836 at Washington-on-the-Brazos, where he signed the Declaration of Independence. After the convention, Augustine was in charge of escorting the Hardin family members to Louisiana during the Runaway Scrape. After returning to Texas, he served in the Army of the Republic of Texas from July 7 to October 7, 1836.
Hardin married Maria Dever, on February 9, 1828, in Liberty. They had seven children, five of whom survived childhood. Maria died in Liberty County in 1844, and Augustine did not remarry. His son by his first marriage, Augustine B. Hardin, Jr., moved to Texas in 1839 and lived with his father before moving to Leon County, Texas. The elder Augustine was a Catholic, the only Hardin to practice the faith after the Texas Revolution. From 1836 until 1871 he spent the majority of his time in Liberty County with his ranching and agricultural operations. In 1849 he was one of the founders of the Liberty Masonic Lodge. He died in Liberty County at his daughter's house on July 22, 1871, and was buried in the Hardin family cemetery north of Liberty. In 1936 the Texas Centennial Commission placed monuments in his honor at his grave and on the Liberty County Courthouse square.