Lynch and McEvoy Families from Rassan

You could try checking the land records called the Tithe Applotment Books (1823-38) or the later Griffith's Valuation (1848-64) if you haven't already. The Tithe Applotment Books (1823-38): Microfilm copies of the books for all of Ireland are available at the National Archives of Ireland (NAI)http://www.nationalarchives.ie/genealogy1/genealogy-records/tithe-applotment-books-and-the-primary-griffith-valuation/ or the Church of Latter Day Saints (LDS). Griffith's is freely available here: www.askaboutireland.com or here:www.failteromhat.com Failte Romhat has lots of other useful links you could try looking at.

The Tithe Applotment List might be of use to you, or at least interesting for you. These lists constitute the only nationwide survey for the period, and are valuable because the heaviest burden of the tithes to the Established Church, the Church of Ireland, fell on the poorest, for whom few other records survive. The information in the Tithes is quite basic, typically consisting of townland name, landholder's name, area of land and tithes payable. Many Books also record the landlord's name and an assessment of the economic productivity of the land. The tax payable was based on the average price of wheat and oats over the seven years up to 1823, and was levied at a different rate depending on the quality of land. For Parishes where the registers do not begin until after 1850, this information can be useful, as they are often the only surviving early records. They can provide valuable circumstantial evidence, especially where a holding passed from father to son in the period between the Tithe survey and Griffith's Valuation.

Civil registration records are available from the General Register Office (GRO). These start from 1864. You can access the website here:http://www.groireland.ie/research.htm Or you might try Valuations office in Dublin (http://www.valoff.ie) which will have a record of the land registry from 1855 to modern times. This will assist in seeing what happened to any land the familymay have owned (as it usually passed on to a relation).

You could also try contacting the Cavan Co Library for further assistance.

Cavan Genealogy,
1st floor,
Johnston Central Library,
Farnham Street,
Cavan Town,
County Cavan.
Tel: +353 (0)49 4361094
Fax: +353 (0)49 4331494
Email: cavangenealogy@eircom.net

Best of luck & if you have any certs you need me to decipher please scan them to me.  & if you are planning on coming this way, I can show you around the area. 

Regards Carmel O'Callaghan