Henry Marshall Elmore, planter, judge, and Confederate infantry officer, was born on July 28, 1816, in Laurens County, South Carolina, son of Gen. John Archer Elmore and Nancy Ann (Martin) Elmore. He was educated at the University of Alabama in Tuscaloosa and served as Macon County judge and state legislator. Elmore was married to Elizabeth Harris on June 26, 1838, and the couple produced six children. The family relocated to Autauga County, Alabama, in the 1840s. In 1855 he was a probate judge in Macon County, Alabama, and moved to Waverly, Texas, in 1856. He is considered a founding father of the town of Waverly.
By 1860 Elmore was a successful farmer in Waverly and owned forty-eight slaves. He enlisted as a private in Company G of the Twentieth Texas Infantry on May 9, 1862, at Camp Travis and was elected colonel. This regiment, known as Elmore's Twentieth, was composed primarily of middle-aged men, many of whom were prominent citizens. It was assigned to guard duty on the Texas Gulf coast from Galveston to the Sabine River and did not see duty outside of the state. The unit was involved in the battles of Sabine Pass and Galveston. The unit played an important role in the Confederate recapture of Galveston in January 1863. Elmore was sent to Tyler, Texas, as the result of a court martial from May 1864 through February 28, 1865, when he returned to Galveston.
Elmore returned to Waverly, San Jacinto County, after the Civil War. In 1866 he served as secretary for a society of former planters known as the Waverly Emigration Society, which held a convention on September 19, 1866. In 1870 he served as president of the board of trustees of the Waverly Male and Female Institute. He died on February 21, 1879, and is buried near his wife in the Old Waverly Cemetery in San Jacinto County.