Red hair is most commonly found at the northern and western fringes of Europe; it is centered around populations in the British Isles. Redheads are commonly associated with the Celtic nations.
In Ireland, the percentage of the population with red hair is estimated to be at around 10%, making it the world's highest concentrated population of red heads.
Great Britain also has a high percentage of people with red hair; in Scotland, around 6% of the population has red hair, with the highest concentration in the world found in Edinburgh. A 1956 study of hair color among British Army recruits also found high levels of red hair in Wales and in the Scottish border counties of England.