Could you please post your message on the Inishkeel (Fintown) parish page here: http://www.irelandxo.com/group/inishkeel-donegal
You could check the 1901 census to see where other Boyles were still living in Ireland at that time. It might help to narrow it down a little. Other cousins could have remained in the area. You can find this here: http://www.census.nationalarchives.ie/search/
You could also try checking the land records called the Tithe Applotment Books (1823-38) or the later Griffith's Valuation (1848-64). Griffith's is freely available here: www.askaboutireland.com or here: www.failteromhat.com Failte Romhat has lots of other useful 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).
You can information about the frequency of the name in the mid-19th century and any other variant spellings of the name here: http://www.irishtimes.com/ancestor/surname/
Please make sure you link anyone else in your family who is interested in their Irish heritage to our site - and indeed anyone else you know of Irish heritage.
Genealogist (Ireland XO)