James Nelson, tradesman and farmer, was born about 1786 and traveled to Texas in November 1821 on the schooner Lively, having reached an agreement with Stephen F. Austin to work in the Austin colony building cabins and stockades and cultivating at least five acres of corn. By 1823 he was serving as tanner and currier in the community at Beeson's Ferry on the Colorado River, near the site of the present town of Columbus. He took the oath of allegiance to the Mexican government on April 20, 1824, and, as one of the Old Three Hundred colonists, received title to a sitio of land in present Colorado County on August 7, 1824. Later in the year, however, unable to pay his debts through inability to collect fees owed to him, Nelson journeyed to Louisiana to obtain employment as an engineer aboard the steamboat Natchitoches. By 1826 he had returned to the Austin colony to engage in farming and stock raising. County censuses for 1823 and 1826 describe him as a widower and father of four children.
Nelson served as a private in the Texas army from March 4 to June 4, 1836, in Capt. William J. E. Heard's Company F, First Regiment, Texas Volunteers. Nelson was among the wounded at the battle of San Jacinto. In recompense for his services he was granted a headright certificate in 1838 for one-third league of land in Colorado County. In 1837 and 1838 he served as coroner of Colorado County. He married Mary Slaughter in Colorado County on January 12, 1840. That year he reportedly held title to 300 acres of land and owned ten slaves.