I am from England and not used to looking for Usa connections.
I am looking for a marriage between James Joseph Kehoe(keogh) born 1869 and Elizathen (Bessie) M Woodward Born 1883 The had first child in Hartford New York in 1906 so looking for a marriage before that. Can anyone advise me where to look thanks.
This information from the FamilySearch Research Wiki might help you, https://familysearch.org/learn/wiki/en/Washington_County,_New_York#.... It doesn't look like the Family History Library has the dates you need but there is still some good info on the wiki about research and a few links.
Here's some info on NY marriage certificates, http://www.vitalrec.com/ny.html
You also may want to look at the USGenweb for New York and then Washington County.