Hi Denis,
Thank you for your message. I hope that someone with information on the family makes a connection with you and helps you to further your research.
In the meantime have you tried looking in church records for information? Most Catholic records are held locally so you may need to write to the local parish priest for possible assistance. One website that you may find useful is the Irish Times where they give an overview of what records are available in specific parishes. It also shows you where copies of the records are available. For Castletown-Geoghegan parish, follow this link:
http://www.irishtimes.com/ancestor/fuses/rcparishmaps/index.cfm?fuseaction=showidrecords&churchid=913&CityCounty=Westmeath&CityCounty=Westmeath&parish=Castletown-Geoghegan
Here are the parish contacts if you would like to get in touch:
V. Rev S?amus Giles PP
Parochial House
Castletown-Geoghegan
County Westmeath
Tel 044-9226118
e-mail castletown8@eircom.net
You could also check for record of the family in the land records pertaining to Ireland in the 19th century. There are two:
The Tithe Applotment Books (1823-1838) found at http://titheapplotmentbooks.nationalarchives.ie/search/tab/home.jsp
and Griffith?s Valuation (1848-1864) found at http://www.askaboutireland.ie/griffith-valuation/
Some other websites that you may find useful are:
The National Archives of Ireland http://www.nationalarchives.ie/genealogy1/genealogy-records/introduction/
The National Library of Ireland http://www.nli.ie/en/family-history-introduction.aspx
Family Search: www.familysearch.org
Genealogy Links: http://www.genealogylinks.net/uk/ireland/westmeath/index.html
From Ireland: www.from-ireland.net
IGP: http://www.igp-web.com/westmeath/
Alternatively you could try contacting Dun na Si Heritage Centre to see if they can be f any assistance, however please note that a fee may apply. Here is their email: dunnasimoate@eircom.net
All the best,
Genealogy Support