On 22 Aug 1779 when Josiah was 31, he married Lydia Marston (42841) , daughter of Caleb Marston (22972) (3 Jul 1699-7 Feb 1778) & Tabitha Page (46925) (21 Aug 1711-30 May 1792), in Hampton, Rockingham County, New Hampshire. Born on 16 Nov 1753 in Hampton, Rockingham County, New Hampshire.40 Lydia died in Hampton, Rockingham County, New Hampshire, on 25 Nov 1817; she was 64.40

Children of Josian and Lydia (Marston) Mason, born at Hampton:
    i. Caleb Mason, b. 21 Aug 1780, d. 27 Jun 1863 at Hampton, m. there 1 Jul 1804 Sally Godfrey (b. 13 Jul 1785 at Hampton, d. there 20 Feb 1873);
    ii. Joseph Mason, b. ca. 1783, d. 10 Mar 1811 at sea, m. at Rye, NH, 25 Jan 1809 Patty W. Foss (d. 1 APR 1828 at Rye);
    iii. Josiah Mason, b. ca. 1785;
    iv. Martha Mason, b. ca. 1787;
    v. Benjamin Mason, b. Feb 1790, d. 22 Jun 1811 at Hampton;
    vi. Tabitha Mason, b. ca. 1793; and
    vii. Shubael Mason, b. ca. 1796, d. 17 Oct 1797 at Hampton.