Sarah married Benjamin Martin.

12 Feb 1717/8 Elizabeth married James Lakin, son of William Lakin (6 May 1655-18 Mar 1735) & Elizabeth Robinson (3 Oct 1668-1 May 1763), in Groton, MA. Born ca 1690 in Groton, MA.

On 22 May 1723 when Isaac was 23, he married Lydia Shattuck (53294) , daughter of John Shattuck (36566) (4 Jun 1666-8 May 1709) & Mary Blood (1 Sep 1672-4 Mar 1756), in Groton, MA. Born on 1 Mar 1704 in Groton, MA.30 Lydia died in Pepperell, MA, on 23 Oct 1783; she was 79.

Isaac and Lydia were second cousins. Their paternal grandfathers were brothers.

Children of Isaac and Lydia (Shattuck) Williams:
    i. Thomas Williams, b. 24 Oct 1724;
    ii. Lydia Williams, b. 26 Oct 1726;
    iii. Jerusha Williams, b. 29 Dec 1728;
    iv. Elizabeth Williams, b. 23 Apr 1730;
    v. Isaac Williams, b. 22 May 1732;
    vi. Sarah Williams, b. 12 Oct 1734;
    vii. Jonathan Williams, b. 25 May 1736;
    viii. Anna Williams, b. 15 Jun 1738; and
    ix. Benjamin Williams, b. ca. 1740.

27 Jan 1725/6 Anna married Samuel Shattuck (53295) , son of Samuel Shattuck (36569) (ca 1673-22 Jul 1758) & Elizabeth Blood (27 Apr 1675-25 Sep 1723), in Groton, MA. Born on 7 Apr 1696 in Groton, MA. Samuel died in Pepperell, MA, on 4 Mar 1775; he was 78.

19 Jan 1723/4 Abigail married Josiah Tucker in Groton, MA.