Map showing frequency of red hair across Europe. Five color-coded ranges: red (over 10%) concentrated in Ireland and Scotland, orange (5-9%) in parts of UK and northern Europe, brown (2-4%) in Scandinavia and Germany, darker brown (1-2%) in central Europe, and darkest brown (under 1%) in southern Europe. Shows clear north-south gradient with highest concentrations in Celtic regions.
I think that's Udmurtia. Udmurts are an Ugric minority people within Russia, and they've got a really high incidence of red hair