Namesakes
Fictional Characters from Books:
1 character
Niall Brigant 2001 The Southern Vampire Mysteries 
Fictional Characters from Television:
1 character
Niall Brigant 2008 True Blood
Irish High Kings:
4 kings
King Niall I Naoighiallach 379-405
King Niall II Frasach 763-770
King Niall III Caille 833-846
King Niall IV Glúin Dubh 915-919
Notable Athletes:
1 cricket, 1 soccer
(cricket) Niall O'Brien 1981-
(soccer) Niall McGinn 1987-