20 Apr. 1735–30 Jan. 1785
See also Thomas Henderson, brother.
Henderson's career took a major step forward in March 1768, when royal governor William Tryon appointed him associate justice on the colony's Superior Court. Tryon, in writing to the British colonial secretary, the Earl of Shelburne, described Henderson as a "gentleman of candor and ability . . . for whom [the inhabitants] entertain an esteem." Henderson's tenure in office occurred during a turbulent period for the Piedmont. As the Regulators reached their zenith in 1770–71, Henderson felt the full fury of their wrath. In September 1770, while court was in session at Hillsborough, Regulators stormed into the town and besieged the courthouse. Henderson managed to escape out a back door, but several other colonial officials, including John Williams, were less fortunate. In November, the Regulators burned Henderson's home near Williamsboro. In the trial following the Battle of Alamance in 1771, he was one of the presiding justices who convicted twelve Regulators, of whom six were executed. When his term ended in 1773, Henderson retired from the bench in order to pursue his real ambition.
From a young age the West had always held a fascination for him. Perhaps as early as the mid-1760s Henderson had begun to formulate a plan of exploration, and while riding the circuit through western North Carolina he had met a young man who shared his enthusiasm. By 1769 Henderson felt the time had come to equip an expedition to explore the lands beyond the Appalachians and to locate areas suitable for settlement. The little band set out on a two-year mission led by Henderson's friend, Daniel Boone.
The company was beset with troubles from the beginning. The governors of North Carolina and Virginia both issued proclamations denouncing Henderson and the company and invalidating any agreement with the Indians. As the proprietors tried to organize the settlers and establish a government in Kentucky, James Hogg, a member of the company, traveled north to Philadelphia to present to the Continental Congress a memorial from the Transylvanians seeking admission as the fourteenth colony. The Congress, appeasing the states' claims to western lands and respecting imperial jurisdiction over the West, wanted no part of the Transylvania colony. Without federal recognition, the colony's fate was sealed. The Transylvania Company lingered for several years but effective control of the land had been lost. Eventually North Carolina and Virginia each granted the company 200,000 acres as compensation for its expense and services in the undertaking. Henderson, though, was far from finished with land speculation. In 1779–80 he spearheaded another group of settlers into the Cumberland Valley in Tennessee and founded French Lick (present-day Nashville).
With peace restored, Granville County elected Henderson to the state legislature in 1781, and he served on the Council of State from 1782 to 1783. His life was cut short by death at age forty-nine. He was buried on his farm where his house still stands near Williamsboro on Nutbush Creek. Henderson was an Anglican and a vestryman in the Parish of Granville. His children were educated by Henry Patillo, an eminent Presbyterian clergyman. Henderson, who was always interested in education, played a key role in the establishment of Granville Hall, an academy begun in 1779. The Hendersons had six children: Fanny (b. 1764), Richard (b. 1766), Archibald (b. 1768), Elizabeth (b. 1770), Leonard (b. 1778), and John (b. 1780).