Around 75% of the working population in Fjarðabyggð, eastern Iceland, are Polish. (This is probably due to the big aluminium smelter situated there. Also the population in Fjarðabyggð is 5 206 persons in total.) Polish citizens are also the largest minority on Iceland as a whole, making up 3% of the population.
Also, for some reason unknown to me, there’s also street signs bilingual in Icelandic and French.