On 17 Nov 1724 when Isaac was 24, he married Mary Jackson (42709) , daughter of Edmund Jackson (2 Aug 1672-26 Feb 1723/4) & Mary Whitmarsh (22792) (12 Jun 1674-5 Jul 1737), in Weymouth, MA. Born on 30 Nov 1696 in Weymouth, MA.83

Perhaps Mary, the wife of Thomas Nash, was the daughter of Sebas and Sarah (Baker) Jackson born at Newton 26 Dec 1687.226

Children of Thomas and Mary (Jackson) Nash, born at Weymouth:
    i. Ruth Nash, b. 1715;
    ii. Mary Nash, b. 1718;
    iii. Sarah Nash, b. 1720; and
    iv. Daniel Nash, b. 24 Feb 1723/4.

Children of Isaac and Mary (Jackson) (Nash) Newcomb, born at Weymouth or Braintree:
    i. Thankful Newcomb, b. 23 Oct 1725, d. ca. Aug 1745 at Weymouth;
    ii. Bethiah Newcomb, b. 28 Nov 1727;
    iii. Thomas Newcomb, b. 15 Jun 1730, d. 15 Jul 1799 at Quincy;
    iv. Nathaniel Newcomb, b. 8 Aug 1732, d. ca. Sep 1747 at Braintree;
    v. Micah Newcomb, b. ca. 1733, d. 6 Jul 1825 at Quincy; and
    vi. Betty Newcomb, b. ca. 1737.