It looks like we have found a DNA connection between 3 McQuillans from Counties Monaghan and Fermanagh, a Cullen from an unknown location in Ireland, and a Collins in the US who believes he can trace back to a Callan family from Meath...and these seem to all be related to the McMahon family who were chiefs in the area...Many different surnames, but first some maps of the McQuillan surname in the mid 1800s and today (click on maps to enlarge, and be sure to compare these with the McCullen and Cullen maps below. If you need the names of the counties, go to http://en.wikipedia.org/wiki/Counties_of_ireland
The maps are very similar (unlike the McCullen surname which essentially disappeared in the last 150 years). There has been a large increase in McQuillans in and around Ballymena in Co. Antrim, and in general I would say that McQuillan is found more in towns and suburbs than Cullen for example, but then Antrim, northern Armagh and Louth are have always been densely populated places. Another change is a decline of the surname in Fermanagh, and a shifting of the main cluster of the surname in Monaghan from the Clones area to an area more to the northeast.
For the Griffith's data, there were many spellings but I think I caught all that contained "Quil", but didn't include on the map surnames like McQuillinan, McQuillcan. The BT phone book for Northern Ireland was easier to search than the Eircom for the Republic, and in the BT book I searched for all variants of Quillan and McQuillan but there were only two listings--one Quillan and one McQuillam. In the Eircom directory, I searched for McQuillan only. (note--I haven't mapped the phone listings for Dublin yet--hope to fix this soon)
