John was born 1732 in Ulster, Armagh, Ireland. He married Ellen Nelson. She was born 1736 in Guilford County, North Carolina, and died 1770 in Guilford County, North Carolina.
In 1759, John was granted 640 Acres near Alamance Church, Guilford County, NC, which he was a member. Tax records show John in 1759 on the tax list of Rowan County, North Carolina. The 1790 and 1800 Census, records show John was in Guilford County, North Carolina. The eastern part of Rowan County was joined with the western part of Orange County to form Guilford County.
Children of JOHN MCADOO and ELLEN NELSON are: i. DAVID MCADOO, b. 1758, Guilford, North Carolina; d. 1815, Dickson, Dickson, Tennessee. ii. SAMUEL MCADOO, b. April 10, 1760, Guilford County, North Carolina; m. HENRIETTA WHEATLEY. iii. JOHN MCADOO. iv. WILLIAM MCADOO. v. JAMES MCADOO, d. 1800.