Ceanannas is based, somewhat loosely, on the uncial script of the Book of Kells.

Ceanannas was first digitized in 1993 by Michael Everson and originally used the MacGaelic character set on the Macintosh platform, and ISO/IEC 8859-14 on the PC. In 2010 Ceanannas version 3 was released in OpenType format, completely compliant with Unicode encoding and with an extended character set.