John (Johannes Lang) Long was the son of Johann Martin Lang (abt. 1702 Germany) and Margaret ? Lang. John had two siblings that we know of. They were: Christopher (1742-1811), and Elizabeth (1762-1805). All 3 children were born in Maryland.
John married Anna Margaret (Fluck) Flook (1753-1815) on 16 June 1776 in the Evangelical Reformed Lutheran Church in Middletown, Frederick, Maryland. They had eight children. They were: Barbara (1777), Elizabeth (1779), Mary Magdelena (1781), Margaret (1784), John Jr. (1787), Stephen Christopher (1790), Christianna Jane (1793), and Catherine (1798).