Hi and welcome to Rootschat
Civil registration began in Ireland in 1864 (only Church of Ireland marriages start from 1845)-before that you would have to rely on parish records.
You could write to the parish priest in Doneraile(Richard and Louisa say they are RC on the 1911 census)to see if he has the baptism/marriage records. On the census Louisa says she was born in Cork -so it could possibly be Doneraile.
Another way would be to trace back from the children - if you apply for one of their birth certificates from the GRO in Roscommon or one of the local county registrars(approx 10 euros)you would learn Louisa's maiden name.
Then possibly trace the marriage. as this was after the start of civil registration in 1864.Sometimes it's quicker to apply to the local registrar(Cork) and I think they accept cash. (click on 'Fees' and scroll down on the link)
The Irish Family History Foundation ahve put a lot of church records on line. It's free to register and search but 5 euros to view any record. There are a couple of entries for Richard Creaghs born around 1864. You can select a parish.
One is in Doneraile in 1867. However it might not be the right one - obtaining the certificates might be a better way.
The IGI also has some entries for Richard Creagh .There are lots of Creaghs from Doneraile and nearby on the IGI. Some names look very impressive. There's a Louise Creagh born in 1872?
There must have been a large family.I tried all sorts of Creagh names - John,Richard,Mary,Elizabeth,Benjamin,Michael - sometimes the IGI won't let you search with just the surname. The address for some of them was Creagh Castle!
If you just do a google search for 'Creagh Castle Cork' you should find some
information on the Creaghs of Doneraile.
I've enclosed some links for you.
http://www.iol.ie/~nodonnel/gentleman'svillage.htmhttp://www.hidden-ireland.com/creagh/index.htmhttp://www.familysearch.org/Eng/Search/frameset_search.asp?PAGE=igi/search_IGI.asp&clear_form=truehttp://corknortheast.brsgenealogy.com/search.php?filename=db_QUIShttp://www.groireland.ie/Hope this helps
Good Luck
Neptune