Cassidy Clan
- Hereditary association promoting and fostering clan kinship, including Cassada and Cassaday. Features photographs of Ballycassidy and County Fermanagh, Northern Ireland, where all Cassidys originated.
- http://www.cassidyclan.org/

Cassidy: Bridget's Place
- Family history of the Cassidy and Loftus families of Ireland and Scotland.
- http://www.esatclear.ie/~brib/