サウスカロライナ植民地
Witherspoon was born near Kingstree in the Province of South Carolina as the son of a Scots-Irish father, Robert Witherspoon (1728–1778) who was born in County Down, Ireland and settled in the Province of South Carolina. His mother was Elizabeth Heathly Witherspoon (1740–1820), who was born in South Carolina. Robert Witherspoon attended local schools.