Though the CARDNO one-name study was registered in 2021, it has been underway since the 1980s. The original assumption was that people bearing the name are likely to be related and by collecting all instances of the name I would be able to identify my own CARDNO ancestors. Collaboration with others researching the name greatly assisted development of the current database.

The study is focused on the name CARDNO.

Similar Scottish names, such as CARNO and CARN(E)Y are excluded. In some parts of the world the name CARDNO is used by families who do not descend from the Scottish.

The family name is from the Buchan placename, Cardno, which derives from the Gaelic carden-ach, meaning copse or thicket place.  The lands of Cardno lie to the south-west of Fraserburgh, Aberdeenshire.

The earliest record of CARDNO as a family name is dated 1476, when William CARDNACH was a flesher in Aberdeen. Andrew CARDNO witnessed a marriage contract in 1498. In 1505, John CARDNO was appointed vicar of Crimond.

Few CARDNOs have achieved any kind of renown. A Google search for the name is most likely to return information about the international engineering services company Cardno Inc., which has its origins in Queensland, Australia. Gerald Fitzgerald CARDNO (1904-1985) was co-founder of the original company.

James Alexander CARDNO was the first professor of psychology at the University of Tasmania.

James Farquhar CARDNO (1912-1975) won a bronze medal at the 1936 Winter Olympics in the four-man bobsleigh event.

The 1911 census of Scotland recorded 248 people with the family name CARDNO, in a total population of 4.8 million. The frequency of the name was about 5 per 100,000 persons throughout the nineteenth century. Almost 90% of CARDNOs in Scotland in 1911 were living in Aberdeenshire. There were 74 CARDNOs in England and Wales in 1911.

Almost 90% of CARDNOs in Scotland in 1911 were living in Aberdeenshire. In England, the name was concentrated in the north east, Yorkshire, and the south east. According to Forebears.io, 34% of CARDNOs globally in 2014 were in Scotland and 24% in England and Wales. The USA had 11%, Canada 9% and Australia 4%.

The database includes names from Scottish statutory BMD registers, Old Parish Registers and published Episcopal registers;  English GRO indexes and online collections of English BMD records; monumental inscriptions and probate indexes from published and online sources; Scottish and English censuses and the English 1939 Register; Canadian and US censuses; online BMD records from Canada, USA, Australia and New Zealand.

Information from the "Cardno Manuscripts" held by Aberdeen City Library and from other CARDNO researchers is also included.

The current CARDNO database is at http://awscott.co.uk/cardno.