Henry Massengill came from North Carolina to the Watauga settlement in 1769 with his pioneer family and established a plantation near the mouth of Boone's Creek adjoining that of William Bean, the first permanent white settler west of the Allegheny Mountains. In 1775 he was appointed to an office in the Watauga Association, which adopted the first written constitution for the government of American-born freemen. He built the Massengill house of worship in 1777, served two years as sheriff of Washington District, was chairman of the committee of safety in 1778, served on the staff of Captain William Edmiston in General Shelby's expedition against the Chicamauga Indians in 1779, and furnished three sons to the Revolutionary Army. Henry and his wife Mary Cobb had six children: Michael, Hal, Solomon, Ailsey, Elizabeth, and Mary. Michael Massengill enlisted in the Revolutionary Army at age 20, fought at Musgrove's Mills, Blackstock, and King's Mountain, was a Regulator in Washington County in 1778, and later helped found Grainger County and served as an early justice of its county court. Hal Massengill enlisted at age 18 and served two years and three months on the frontier and in North Carolina; Solomon Massengill served under General Sumpter in the Revolutionary War, lost his right ear to a British dragoon at Blackstock, and later helped found Anderson County. Elizabeth Massengill married Isaac Thomas, an Indian scout, trader, Revolutionary War soldier, and founder of Sevier County, and Mary Massengill married silversmith William Atkinson, who with his brother made Tennessee's first great seal in 1801. In a memoir, Henry recalled that after Reverend Charles Cummings came to Watauga in April 1777 and urged the settlers to build a house of worship, he furnished the logs, boards, and timbers for a large meetinghouse with benches for the Massengill and Cobb enslaved people, numbering 151 souls, and that the house was completed by July 1777, later burned by Tories while he was away with Shelby in 1779. The account also traces the Massengill family from Yorkshire, England, through Daniel Massengill's emigration to Virginia in 1645 and settlement there in 1653, and links Henry to that line. It further records that William Cobb, Henry's brother-in-law, followed him to Watauga, served on the first Washington County court, and lived at Rocky Mount, which Governor Blount used in 1790 as the capital of the Southwest Territory, while Andrew Jackson stayed there for six weeks in 1788 before receiving his license to practice law in Washington County.