Ephraim married Lydia Merriman (28796) , daughter of Cpl. Caleb Merriman (May 1665-19 Jul 1703) & Mary Preston (12139) (12 Apr 1674-28 Nov 1755). Born on 12 Nov 1702 in Wallingford, CT.90 Lydia died on 25 Dec 1785; she was 83.55 Buried in Hillside Cemetery, Cheshire.

Children of Ephraim and Lydia (Merriman) Cook, born at Wallingford:90
    i. Mary Cook, b. 9 Feb 1723, d. 13 Feb 1723;
    ii. Mamre Cook, b. 21 Dec 1723, m. Daniel Hotchkiss;
    iii. Lydia Cook, b. 2 Mar 1726;
    iv. Mary Cook, b. 7 Apr 1728, d. 31 oct 1812 at Cheshire, m. 1st at Wallingford 26 Oct 1746 John Smith, m. 2nd at Cheshire 23 Feb 1775 Moses Blakeslee;
    v. Ephraim Cook, b. 7 Sep 1730, d. 18 Jan 1789 at Cheshire, Capt., m. at Wallingford 1 Jan 1752 Elizaeth Hull (b. 14 Feb 1733 at Wallingford, dau. of John & Sarah (Ives) Hull);
    vi. Tirzah Cook, b. 5 Oct 1733, m. Samuel Smith of Bristol;
    vii. Elam Cook, b. 10 Nov 1735, d. 3 Feb 1808 at Cheshire, m. at Wallingford 8 Jan 1761 Abigail Hall (b. 20 Mar 1740 at Wallingford, d. 26 Sep 1816, dau. of Joseph & Abigail (Judd) Hall);
    viii. Elizabeth Cook, b. 10 Feb 1738, m. Eleazer Brown;
    ix. John Cook, b. 29 Dec 1739, d. 1 Oct 1764 at Cheshire, m. Obedience Stepvens (b. ca. 1746, d. 25 oct 1830 at North Branford, dau. of Thomas & Desire (Smith) Stevens, she m. 2nd at Wallingford 7 Dec 1769 Daniel Ives, m. 3rd Rufus Hoadley of Northford); and
    x. Thankful Cook, b. 19 Sep 1742.55