The roots of the Finnan surname in Ireland are somewhat unclear; it seems that the name was both native Irish Gaelic, and Norman. The Gaelic name "ó Fionnáin" seems to be derived from Gaelic word "fionn, "which means "fair." This Gaelic name has been Anglicized as Finan and Fanning, both of which are also Norman names that came to Ireland in the 12th century.
The surname Finnan was first found in County Mayo (Irish: Maigh Eo) located on the West coast of the Republic of Ireland in the province of Connacht, where they were of the Hy Fiachrach Sept. One notable bearer of the personal name who lived several centuries prior to the introduction of hereditary surnames was St. Finan (Finan of Lindisfarne) who died in 661 AD, and achieved repute for his missionary work in England. He was Bishop of Lindisfarne (651-661) and he converted the kings Sigebert of Essex and Peada of the Middle Angles to Christianity. 
This web page shows only a small excerpt of our Finnan research. Another 63 words (4 lines of text) covering the years 1659, 1901 and 1847 are included under the topic Early Finnan History in all our PDF Extended History products and printed products wherever possible.
^ Smith, George (ed), Dictionary of National Biography. London: Smith, Elder & Co., 1885-1900. Print
^ Filby, P. William, Meyer, Mary K., Passenger and immigration lists index : a guide to published arrival records of about 500,000 passengers who came to the United States and Canada in the seventeenth, eighteenth, and nineteenth centuries. 1982-1985 Cumulated Supplements in Four Volumes Detroit, Mich. : Gale Research Co., 1985, Print (ISBN 0-8103-1795-8)