Hi Col,
Thanks very much for your message-I hope that it helps you get a new start on your research!
It would be much easier however if you could narrow down place of origin. Most Irish record sources- church records, land records, census records- are based on specific locations. Until you know a specific location within Ireland, preferably a parish or placename, it may be difficult to do anything more with these records.
Do you have any documentation pertaining to the family that mentions any place names at all? This can include wills, marriage/death records,census records, letters, diary entries etc.
There are some places where you can search online, however these websites do not have complete collections:
www.familysearch.org has a huge database of genealogical records including some church records for Ireland.
www.rootsireland.ie have a large collection of Irish Church records, however you have to pay to use this site.
Mains was not a very common surname in 19th century Ireland as you can see here:
http://www.irishtimes.com/ancestor/surname/index.cfm?fuseaction=Go.&Surname=Mains&UserID=
Here is a link to the land record known as Griffith?s Valuation, this is where the data from the above pie chart comes from:
http://www.askaboutireland.ie/griffith-valuation/index.xml?action=doNameSearch&Submit.x=38&Submit.y=17&Submit=Submit&familyname=mains&firstname=First+Name&baronyname=&countyname=&unionname=&parishname=
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
The National Archives UK ? genealogy search: http://www.nationalarchives.gov.uk/records/looking-for-person/
The Public Records Office of Northern Ireland http://www.proni.gov.uk/index/family_history.htm
From Ireland: www.from-ireland.net
Irish Genealogy Tool kit: http://www.irish-genealogy-toolkit.com/
Genealogy Links: 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
The National Archives UK ? genealogy search: http://www.nationalarchives.gov.uk/records/looking-for-person/
The Public Records Office of Northern Ireland http://www.proni.gov.uk/index/family_history.htm
Irish Times: http://www.irishtimes.com/ancestor/index.htm
Irish Genealogy Tool kit: http://www.irish-genealogy-toolkit.com/
Remember to post any new information that you find here. The more information you post, the more likely it is that one of our volunteers will be able to advise or assist you. Also include information concerning which sources you may have already used so others may further your search.
Kind regards,
Genealogy Support