On 11 Sep 1787 when Cooper was 23, he married
Abigail Bemis (42365) , daughter of
Joseph Bemis (37941) (10 Apr 1723-) &
Ruth Simonds (22526) (29 Dec 1727-), in Waltham, MA.
27 Born on 18 May 1759 in Waltham, MA.30 Abigail died in Cambridge, MA, on 24 Mar 1797; she was 37.