MJ Networks and surname distribution mapping show a clear association between the number of founding ancestors and the number of geographical areas where the Surname is concentrated. Previous research has shown using Median-Joining (MJ) networks that Sullivan, McEvoy, and Donohoe were associated with 1(B), 2 (M and N), and 3 (J, K, and L) founding ancestors respectively (McEvoy and Bradley, 2006). Similarly Sullivan is concentrated in a single geographical location on the borderland between counties Cork and Kerry, while McEvoy is associated with 2 separate locations in counties Laois, and Down. Donohoe is associated with at least 3 geographically distant locations in counties Kerry, Galway, and Cavan. Distribution maps are taken from the Irish Origenes database (www.irishorigenes.com).