S. Slade Barnett, farmer and legislator, was born about 1807 in Kentucky. He married Talitha Cumi Woods in that state, and they had at least three children. The family moved to Sabine County, Texas, sometime between August 26, 1838, when his daughter Frances was born in Kentucky, and December 21, 1839, when he received a conditional certificate for land in Texas. Barnett represented Sabine County in the House of the Fifth Congress of the Republic of Texas; he took his seat on November 13, 1840, eleven days after the beginning of the session. He later moved to Rusk County, where he was elected a county commissioner in 1848 and a justice of the peace in 1850. On July 15, 1860, Barnett married Mary E. Kilgore in Rusk County. Two years earlier his daughter had married Constantine Buckley Kilgore. Barnett's estate was filed for probate in Gregg County on August 10, 1877.