Thomas Gillespie was a large plantation owner in mid-to-late 18th-century North Carolina and served as commissary of the Rowan County Regiment in the North Carolina militia during the American Revolution. He spent his early life in Augusta County, Virginia before migrating to Anson County, North Carolina in about 1750, where he lived most of his life on Sills Creek in the area that became Rowan County, North Carolina in 1753. He and his wife and son were the first white settlers west of the Yadkin River. He owned a plantation of over 1,000 acres on Sills Creek in Rowan County, as well as 6,000 acres in the area of western North Carolina that became part of the state of Tennessee in 1796. He was an early elder in the Thyatira Presbyterian Church in Rowan County, which had been established by 1750. Thomas was the great-grandfather of U.S. President James K. Polk through the lineage of his daughter Lydia, who married Captain James Knox and gave birth to Jane Gracey Knox, mother of the President.

The Rowan County Regiment was originally established in about August 1, 1775 as a local militia in Rowan County in the Province of North-Carolina. When the North Carolina Provincial Congress authorized thirty-five existing county militias to be organized on September 9, 1775, the Rowan County Regiment was included and all officers were appointed with commissions from the Provincial Congress. The members of the Rowan County Regiment were mostly from what was Rowan County at the time. Prior to establishment of the Rowan County Regiment, many of its officers were active in the Rowan County Committee of Safety. The regiment included 160 known companies and one or more of these companies were engaged in 36 known battles or skirmishes during the American Revolution. After the establishment of the Rowan County Regiment, several other counties were created from Rowan County, including Burke County in 1777, Iredell County in 1788, Davidson County in 1822 and Davie County in 1836.