Hi,
Thank you for your message.
Have you tried looking for information in Church records? Most Catholic records are held locally. One website which may be of help to you is the irishtimes. Here they give an overview of what records are available in specific parishes. For Loughinisland follow this link:
http://www.irishtimes.com/ancestor/fuses/rcparishmaps/index.cfm?fuseaction=showidrecords&CityCounty=Down&parish=Loughinisland&churchid=435
For Church of Ireland records check:
http://ireland.anglican.org/about/42
http://www.nationalarchives.ie/
http://www.proni.gov.uk/index/family_history/family_history_key_sources.htm
Also, check www.irishgenealogy.ie/index.html Catholic and Church of Ireland records are currently being uploaded here free of charge. However, this is an ongoing project so not all records are available yet.
Do you know much about their emigration? Generally more information was given at the port of arrival rather than that of departure, so this may be a place to find some information. For immigration information in the US check the National Archives at http://www.archives.gov/research/immigration/
Given the dates of their emigration they were most likely processed at Castlegarden. You can search their databases here:
http://www.castlegarden.org/
Some other websites which may help you 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
Remember to post as much information as you can with regard to the people you are researching. 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