Abernathy was born in Lunenburg, Virginia, on February 25, 1795, a native of the Old Dominion. He was the son of Blackstone Abernathy (1767–1850) and Elizabeth Peterson Locke (1771–1849). His ancestors on both sides settled in Virginia prior to the American Revolutionary War (1775–1783). His father was one of the early pioneer settlers of Fayette County, Kentucky where they moved in 1797 and where Abernathy was raised. They and moved to Howard County, Missouri in 1817.^[3][2][4]

Abernathy was married three times and had four sons and eight daughters.^[5] He was the father of Nancy Harrison Abernathy who married Dr. Hugh James Glenn, a wealthy California rancher and politician.^[6][2][7][8] He married Jennie Winn on June 10, 1817 in Fayette County, Kentucky. They had four children. She died on October 13, 1822. He then moved to Ralls County, Missouri in ca. 1823 and stayed in Ralls for about nine years. On May 11, 1826, he marrid Rosanna Davis in Ralls County. They had eight children.^[5]

Abernathy became a farmer in New Madrid, Missouri and was in 1811–1812 New Madrid earthquakes. He lost everything in the quake. He taught school in Howard County, Missouri for a number of years.^[5][4]

He was a soldier in the War of 1812 from February 8, 1815 - March 7, 1815. Private in Captain James Dudley's Kentucky Militia^[1] He received a Widows' Pension (pension #WC-34734 on June 15, 1887.^[9]

Abernathy was a member of the Whig Party, and later became a Republican. He began his political career in the early 1830s.^[10] He was one of the first settlers of Paris, Missouri, Monroe County, Missouri in 1831. The town was laid out by Abernathy, James C. Fox, and E. W. McBride, and in 1837, contained seven stores and a number of families.^[11] In Paris, he started a school for early settlers. He was a resident of Monroe County for over half a century, prior to its organization as a county on January 6, 1831. At this time, he was appointed him commissioner to sell the school lands. On March 10, 1832, he and seven others organized the first Christian Church in Paris. The church was built in a gothic style of brick with four rooms at a cost of $11,000 (equivalent to $335,720 in 2023).^[4][3]

In Paris, Missouri, Abernathy studied law and applied for a license after becoming interested in law after solving a case about a Bee gum that was stolen. He went before Judge Jack Gordon and was admitted to the bar in early 1831 when he was thirty-six years of age. He was one of the earliest attorneys to practice law in Monroe County.^[12][2][4]

In 1831, Abernathy was the first appointed Treasurer of Monroe County and held that office for 12 years until he became district attorney in 1843. Abernathy who settled in Madison, in Monroe County, Missouri in 1836, named the town after President James Madison. Madison was only 12 miles west of Paris, Missouri. In 1837, he laid out and dividing 40 acres of land in the town into 90 lots, which he sold for $1,100 (equivalent to $29,622 in 2023).^[4]: p173 On June 28, 1841, Abernathy married, for the third time, Jane Davis. They had three children together.^[5]

In 1840, the first newspaper published in Monroe County was the Missouri Sentinel. In 1843, the paper was sold, and its name changed to the Paris Mercury. In 1844, Abernathy owned and edited the paper with John Adams. In 1845, he became the sole owner and ran it for seven years.^[4] He 1851 he published the Lagrange Missourian (was the Free Press), which was a new Whig paper at La Grange, Missouri, Lewis County, Missouri.^[13]

In November 1838, Abernathy was a prosecuting district attorney for the 4th Judicial Circuit of the Missouri Circuit Courts that was a 300-mile circuit and extended to twelve counties, composing Northeastern Missouri. He traveled the circuit three times a year on horseback. He held this office for ten years.^[14][4][2] In 1850, Abernathy was a candidate to represent the Third District in the Missouri State Senate.^[15]

Abernathy was then elected county court clerk for seven years. He was a notary public for many years.^[5] He was a constable, then Justice of the peace for sixteen years.^{[6] [2]} During the American Civil War he was a Union man.^[4]

Abernathy ran for judge of the Monroe county court. He ran against John Quarles and Ephriam Poet. He won the election and was re-elected a second term by Governor Thomas Clement Fletcher.^[4]

Abernathy died at his home in Paris, Missouri on January 29, 1886, at the age of 90 years. At the time of his death, he was the oldest man in Monroe County.^[6][3]

• Biographies of Judge James R. Abernathy
• The Abernathy DNA Project