The following table shows the incidence, and areas of highest concentration, of the most frequent family names (from a total of 379 unique surnames; and 1876 individual householders) listed in the 1828 Tithe Applotment Books for Creggan Parish. The 31 family names (8.2% of the total names) account for 784 (41.8%) of the total families.

The figures, while indicative, are not accurate for several reasons.

• The Books do not identify separately those who lived in the townland, and those who rented land there while living elsewhere. Therefore there is some double counting as individuals may be named in two or more townlands.
• The Books do not group land plots to a common rental. Therefore similar names in a single townland may indicate separate individuals, or the same one with more than one non-contiguous plot.