There are at present 60,000 of the Kelley name in Ireland. It is the second largest family name after Murphy. A quarter of a million people bear this name in the U.S.A. and 24,000 in Canada. There are 120,000 Kellys in Great Britain and 50,000 in Australia. The remainder are scattered all over the world. Many people bearing this name have distinguished themselves in their adopted countries.

Hereditary Officers
Like all the other great ruling families of the time the O Kellys had their own hereditary officers who were charged with the various tasks and special needs and undertakings of common interest.

Customs & Laws
As Lords of Ui Maine the O Kellys enjoyed numerous customs and priviledges grew around the clann.

The Book of O Kellys
The history of the O Kellys was finally written in 1394AD some thirteen years after death of William O Kelly. Named the Book of O Kellys ( or the Book of Ui Maine) it is amongst Irelands finest ancient manuscripts and is held as a national treasure.

Credit to: extracts reproduced from copyright Dr. Joseph Kelly. Kelly Clann Association

Wikipedia: The O Kellys

Uí Maine has often been called "O Kelly Country" because of its rich background with the O Kelly family and descendants. The O Kelly family has dated back to the 5th century being very influential of the Uí Maine kingdom. Within just a century, 20 O Kellys ruled over Uí Maine. The O Kellys found their demise in the 17th century with the steady decline of their fortunes in Ireland. The last tragedy to hit the O Kellys was the great famine of 1845-47. Large numbers died because of the blight that had arrived and caused the potato to rot. After the "great famine" many Irish people immigrated all over the world, resulting in the O Kelly (Kelly,Kelley) name spread throughout the globe.

Following information is from a great cousin who contacted me recently, I love finding cousins!

I sent in DNA samples to the National Geographic Genographic Program. I sent in the YDNA (DNA passed father to son) sample and my brother, Rick, sent in the mtDNA (passed mother to children) sample in order to share the cost. When I received my results from the National Geographic Society, I forwarded the results to Family Tree DNA (http://www.FamilyTreeDNA.com ). Family Tree DNA is a DNA database that runs computer matches for various markers in the DNA that indicate family relationships. I also joined the Kelley/Kelly/O'Kelly/O'Kelley group at Family Tree DNA. They tabulate the results of matches within the Kelly group. The coordinator of the Kelly Group sent me this Kelly information:

Our 150 Test Results represent 97 unique, unrelated, KELLY/KELLEY/O'KELLY Families. This means that when Surnames were adopted in Ireland about 900 AD that 97 different Families adopted the Surname KELLY (Gaelic Equivalent). DNA Testing is the only practical method to determine from which KELLY Clan we descend. Since there are a large number of Unique KELLY Clans we are going to have to get a large number of participants to find matches for those of us who haven't yet found a match.

Studies done by geneticists at Trinity University in Dublin indicate that Murphy and Kelly are the two most popular Surnames in Ireland. However, DNA Studies carried out by the University indicate that the large number of people with surname Kelly is due to multiple family founders as opposed to a single patrilineal line with a large number of descendants.

I subsequently received the following message from Family Tree DNA:

The (following) group are descendants of "The O'Kelly of Uí Maine", who was High King of Ireland about the year 160 AD. (84928)Walter Lionel Mary Gerard O'Kelly is the current "Chief of the Clan". (N42001)Donald Ollie Kelley, (N42704)Gerard Joseph Kelly, (N59073)Tim Kelly, (107869)Joseph Patrick Kelly, and (N33146)Steve Kelly are the other members of the group and have 0 Genetic Distance for 12 Markers.

I have ordered an upgrade from a 12 marker to a 67 marker test. I await the results. By the way, "Uí Maine" is Gaelic and pronounced sort of like "High Many" in English. Uí Maine (it has an "accent thing" over the "i") is located in western Ireland bounded roughly by a line joining Galway, Roscommon, and Limerick.