I found the following Pedigree chart on www.familysearch.org for Adam Ritchey. Three are listed from Ireland, two in particular from Antrim. This one lists numerous descendants and also has a link to an Ancestry.com Family Tree. I am curious as well, as I have the Ritchey surname in my line. We might have a connection somewhere along the line. Please let me know if you'd like to look into this line further and I'll be glad to help in any way I can.
The Church of Jesus Christ of Latter-day Saints, "Pedigree Resource File," database, FamilySearch(https://familysearch.org/ark:/61903/2:2:3WV7-XR1 : accessed 2016-12-05), entry for Adam /Ritchey/.