Cornelius married Abigail Merritt (53597) , daughter of Thomas Merritt (36910) (ca 1721-1804) & Jane Nichols (47615) (say 1728-aft 1803). Born on 7 Oct 1766 in Scituate, MA.52 Abigail died in Troy, Rensselaer County, New York, on 9 May 1843; she was 76.

Abigail, also known as Nabby, Merritt.

Children of Cornelius and Abigail (Merritt) Williamson:
    i. Ransom Williamson;
    ii. Jane Williamson, d. unmarried at Troy, lived many years on River Street, Troy;
    iii. Lyman Williamson, b. 9 Aug 1798 at Killingly, CT;
    iv. Lucy Williamson, d. ca. 1870, bur. at Troy, m. Ezra Smith Howard (d. 1 Apr 1878);
    v. Horatio Nelson Williamson, b. ca 1801, d. unmarried 2 Nov 1835, bur. at Troy;
    vi. Mercy Williamson, d. before 1857, m. Joshua Crandall (b. ca. 1805 at Troy, d. there Dec 1857);
    vii. Thomas Merritt Williamson;
    viii. Cornelius Williamson; and
    ix. Caleb Williamson, b. 1812.187