When Cpt. Thomas Marcus Humphrey Jr. was born on 2 June 1742, in Philadelphia Monthly Meeting, Philadelphia, Pennsylvania, United States, his father, Thomas M Humphrey Sr., was 31 and his mother, Hannah Yarbrough, was 26. He married Mary Marks on 19 February 1760, in Chester, Pennsylvania, United States. They were the parents of at least 14 sons and 13 daughters. He died on 7 June 1822, in Bluemont, Loudoun, Virginia, United States, at the age of 80, and was buried in Ketoctin Baptist Church Cemetery, Purcellville, Loudoun, Virginia, United States.