A separate family, the O Donnghalaigh, appear in the records in the barony of Lower Ormond in Co. Tipperary in the middle ages but history appears to have unkind to them; very few of the name remain in the area.
The name was ranked 67th most common in 1890 and 54th overall in 1996; while only 98th in the Republic, it was 27th in Northern Ireland, reflecting its northern origins. Similarly, placenames reflecting the family presence are exclusively northern, with 2 Ballydonnellys and a Killydonnelly in Antrim, Killdonnelly in Monaghan, and Donnellystown in Louth.
.Charles Donnelly (1914-1937) was one of the most promising of the group of young writers emerging in the mid-1930s; he was killed fighting in the International Brigade in Spain at the age of 22.
Dervilla Donnelly is one of Ireland?s most distinguished scientists. She is Professor of Phytochemistry at University College Dublin and was elected President of the Royal Dublin Society in 1981.