The Celtic nations or Celtic countries are a group of geographical regions in Northwestern Europe where the Celtic languages and cultural traits have survived.

The six regions widely considered Celtic countries in modern times are Brittany (), Cornwall (), Ireland (), the Isle of Man ( or ), Scotland (), and Wales (). In each of these six regions a Celtic language is spoken to some extent: Brittonic or Brythonic languages are spoken in Brittany (Breton), Cornwall (Cornish), and Wales (Welsh), whilst Goidelic or Gaelic languages are spoken in Scotland (Scottish Gaelic), Ireland (Irish), and the Isle of Man (Manx). Galicia is also often considered a Celtic country.

Before the expansion of ancient Rome and the spread of Germanic and Slavic tribes, much of Europe was dominated by Celtic-speaking cultures, leaving behind a legacy of Celtic cultural traits. Certain regions with evidence of Celtic influence in northwestern Iberia, such as Asturias, northern Portugal, León, and Cantabria (historically known as Gallaecia and Astures), are not typically considered Celtic nations. Unlike with the Insular Celtic languages, there is no record of Celtic languages surviving into the modern era within these regions. Similar evidence of a pattern of Celtic influence without the long-term survival of Celtic languages is also found in various regions across Europe, including parts of Italy, Austria, and the Czech Republic.

The concept of the Celtic nations is widely promoted by pan-Celtic movements, including political and cultural organizations like the Celtic League or International Celtic Congress.

Six recognised nations Each of the six nations has its own Celtic language. In Brittany, Ireland, Scotland, and Wales these have been spoken continuously through time, while Cornwall and the Isle of Man have languages that were spoken into modern times but later died as spoken community languages. In the latter two regions, however, language revitalisation movements have led to the adoption of these languages by adults and produced a number of native speakers.

Ireland, Wales, Brittany, and Scotland contain areas where a Celtic language is used on a daily basis; in Ireland these areas are called the Gaeltacht; in Wales Y Fro Gymraeg, Breizh-Izel (Lower Brittany) in western Brittany. Generally these communities are in the west of their countries and in more isolated upland or island areas. Welsh is much more widespread, with many people in the north and west speaking it as a first language, or equally alongside English. Public signage is in dual languages throughout Wales and it is now a requirement to possess at least basic Welsh in order to be employed by the Welsh government. The term Gàidhealtachd historically distinguished the Gaelic-speaking areas of Scotland (the Highlands and islands) from the Lowland Scots (i.e. Anglo-Saxon-speaking) areas. This term has also been adopted as the Gaelic name of the Highland council area, which includes non-Gaelic speaking areas.

In Wales, the Welsh language is a core curriculum (compulsory) subject, which all pupils study. Additionally, 20% of schoolchildren in Wales attend Welsh medium schools, where they are taught entirely in the Welsh language. In the Republic of Ireland, all school children study Irish as one of the three core subjects until the end of secondary school, and 7.4% of primary school education is through Irish medium education, which is part of the Gaelscoil movement.

Other regions

Parts of the northern Iberian Peninsula, namely Galicia, Cantabria, Asturias in Spain, and the North Region, Portugal, also lay claim to a Celtic heritage. These regions are not traditionally included among the six primary "Celtic nations" owing to the absence of a living Celtic language, but archaeological and historical evidence points to a significant Celtic influence, particularly in the ancient region of Gallaecia, which encompassed modern Galicia and northern Portugal.

Historical and archaeological influence Numerous archaeological findings, such as castros (hill forts) and artifacts bearing Celtic motifs, support the presence of Celtic-speaking cultures in Gallaecia dating back to at least the Iron Age. Classical sources, including Strabo and Pomponius Mela, described the Gallaeci and Astures tribes as Celtic, noting similarities in cultural practices and languages with the broader Celtic world.

Toponymy and linguistic substrates While no Celtic language has been spoken in northern Iberia since the early Middle Ages, traces of a Celtic linguistic substratum persist in local place names and vocabulary. Toponyms with Celtic roots, such as those ending in "-briga" (meaning "fortress" or "hill"), are common in Galicia and northern Portugal.

Cultural revitalization of Celtic heritage In recent decades, there has been a revival of interest in Celtic heritage across Galicia, Asturias, and northern Portugal. These regions actively participate in pan-Celtic events such as the Festival Interceltique de Lorient, where Galicia and Asturias are recognized alongside the six core Celtic nations. The annual Ortigueira's Festival of Celtic World in Galicia, one of Europe's largest celebrations of Celtic music and culture, attracts performers and audiences from across the Celtic world.

Irish was once widely spoken on the island of Newfoundland, but largely disappeared by the early 20th century. Vestiges remain in words found in Newfoundland English, such as scrob for "scratch" and sleeveen for "rascal."Language: Irish Gaelic, Newfoundland and Labrador Heritage website. There are virtually no known fluent speakers of Irish Gaelic in Newfoundland or Labrador today, though memorized passages survive in traditional tales and songs.

Canadian Gaelic dialects of Scottish Gaelic are still spoken by Gaels in parts of Atlantic Canada, primarily on Cape Breton Island and nearby areas of Nova Scotia. In 2011, there were 1,275 Gaelic speakers in Nova Scotia,Statistics Canada, NHS Profile 2011, by province. and 300 residents of the province considered a Gaelic language their "mother tongue."Statistics Canada, 2011 Census of Canada, Table: Detailed mother tongue

Patagonian Welsh is spoken principally in Y Wladfa in the Chubut Province of Patagonia, with sporadic speakers elsewhere in Argentina. Estimates of the number of Welsh speakers range from 1,500Western Mail (Cardiff, Wales). 27 December 2004. Patagonia Welsh to watch S4C shows. to 5,000.

Celtic languages The Celtic languages form a branch of the greater Indo-European language family. SIL Ethnologue lists six living Celtic languages, of which four have retained a substantial number of native speakers. These are the Goidelic languages (Irish, Scottish Gaelic, and Manx, which are both descended from Middle Irish) and the Brittonic languages (Welsh, Breton and Cornish, which are both descended from Common Brittonic).

In 2010, there were more than 1.4 million speakers of Celtic languages.

Celtic identity

Formal cooperation between the Celtic nations is active in many contexts, including politics, languages, culture and music.

The Celtic League is an inter-Celtic political organisation, which campaigns for the political, language, cultural and social rights, affecting one or more of the Celtic nations.

Established in 1917, the Celtic Congress is a non-political organisation that seeks to promote Celtic culture and languages and to maintain intellectual contact and close cooperation between Celtic peoples.

Festivals celebrating the culture of the Celtic nations include the Festival Interceltique de Lorient (Brittany), Ortigueira's Festival of Celtic World (Galicia), the Pan Celtic Festival (Ireland), CeltFest Cuba (Havana, Cuba), the National Celtic Festival (Portarlington, Australia), the Celtic Media Festival (showcasing film and television from the Celtic nations), and the Eisteddfod (Wales).

Inter-Celtic music festivals include Celtic Connections (Glasgow), and the Hebridean Celtic Festival (Stornoway). Due to immigration, a dialect of Scottish Gaelic (Canadian Gaelic) is spoken by some on Cape Breton Island in Nova Scotia, while a Welsh-speaking minority exists in the Chubut Province of Argentina. Hence, for certain purposes—such as the Festival Interceltique de Lorient—Gallaecia, Asturias, and Cape Breton Island in Nova Scotia are considered three of the nine Celtic nations.

Sporting competitions involving teams from Ireland, Scotland and Wales have been held in rugby union (Pro14—formerly known as the Celtic League), athletics (Celtic Cup) and association football (the Nations Cup—also known as the Celtic Cup).

The Republic of Ireland enjoyed a period of rapid economic growth between 1995 and 2007, leading to the use of the phrase Celtic Tiger to describe the country. Aspirations for Scotland to achieve a similar economic performance to that of Ireland led the Scotland First Minister Alex Salmond to set out his vision of a Celtic Lion economy for Scotland, in 2007.

Genetic studies A Y-DNA study by an Oxford University research team in 2006 claimed that the majority of Britons, including many of the English, are descended from a group of tribes which arrived from Iberia around 5000 BC, before the spread of Celtic culture into western Europe. However, three major later genetic studies have largely invalidated these claims, instead showing that haplogroup R1b in western Europe, most common in traditionally Celtic-speaking areas of Atlantic Europe like Ireland and Brittany, would have largely expanded in massive migrations from the Indo-European homeland, the Yamnaya culture in the Pontic–Caspian steppe, during the Bronze Age along with carriers of Indo-European languages like proto-Celtic. Unlike previous studies, large sections of autosomal DNA were analyzed in addition to paternal Y-DNA markers. They detected an autosomal component present in modern Europeans which was not present in Neolithic or Mesolithic Europeans, and which would have been introduced into Europe with paternal lineages R1b and R1a, as well as the Indo-European languages. This genetic component, labelled as "Yamnaya" in the studies, then mixed to varying degrees with earlier Mesolithic hunter-gatherer or Neolithic farmer populations already existing in western Europe. Furthermore, a 2016 study also found that Bronze Age remains from Rathlin Island in Ireland dating to over 4,000 years ago were most genetically similar to modern Irish, Scottish and Welsh, and that the core of the genome of insular Celtic populations was established by this time.Neolithic and Bronze Age migration to Ireland and establishment of the insular Atlantic genome "Three Bronze Age individuals from Rathlin Island (2026–1534 cal BC), including one high coverage (10.5×) genome, showed substantial Steppe genetic heritage indicating that the European population upheavals of the third millennium manifested all of the way from southern Siberia to the western ocean. This turnover invites the possibility of accompanying introduction of Indo-European, perhaps early Celtic, language. Irish Bronze Age haplotypic similarity is strongest within modern Irish, Scottish, and Welsh populations, and several important genetic variants that today show maximal or very high frequencies in Ireland appear at this horizon. These include those coding for lactase persistence, blue eye color, Y chromosome R1b haplotypes, and the hemochromatosis C282Y allele; to our knowledge, the first detection of a known Mendelian disease variant in prehistory. These findings together suggest the establishment of central attributes of the Irish genome 4,000 y ago."