Isaac Fenner is not listed in our DAR Patriot Database. This does not mean he did not serve in some capacity during the Rev. War, only that no one has applied for DAR membership using him/or his service.
You can go to: www.dar.org
Click on "Membership"
There is a form you can click on to contact DAR & they will have someone from a chapter near your home contact you about becoming a DAR member.
Gook Luck with your searching.