Anglo-Celtic citizens are those of the British and the Celtic descent. The concept is mainly relevant outside of Great Britain and Ireland, particularly in Australia but also in Canada, the United States of America, New Zealand and South Africa, where a significant diaspora is located.
The term is a combination of the combining form Anglo- and the adjective Celtic. Anglo-, meaning English is derived from the Angles, a Germanic people who settled in Britain (mainly in what is now England) in the middle of the first millennium. The name England originates from these people. Celtic,in this context, refers to the people of Ireland, Scotland, Wales, the Isle of Man and Cornwall.
Recorded usage dates as far back to at least the mid-19th century. A newspaper of the name, The Anglo-Celt (pronounced in this case as 'Anglo-Selt'), was founded in County Cavan in Ireland in 1846. In an 1869 publication, the term was contrasted with Anglo-Saxon as a more appropriate term for people of Irish and British descent worldwide:
"Anglo-Saxon," as applied to the modern British people, and Britannic race, I believe every impartial scholar will agree with me in thinking a gross misnomer. For if it can be shown that there is a large Celtic element even in the population of England itself, still more unquestionable is this, not only with regard to the populations the British Isles generally, but also with reference to the English-speaking peoples of America and Australasia. Even the English are rather Anglo-Celts than Anglo Saxons; and still more certainly is Anglo-Celtic a more accurate term than Anglo-Saxon, not only for that British nationality which includes the Scots, the Irish and the Welsh; but also for that Britannic race, chief elements in the formation of which have been Welsh, Scottish and Irish immigrants.