On 7th day of July 1941, 40,000 US Marines landed in Iceland to replace the 25,000 British troops stationed they since the UK had invaded the year before. Given the the population of Iceland was only 120,000 including women and children, you had more US Marines on the island then you had Adult native males.
http://en.wikipedia.org/wiki/Iceland_during_World_War_II
The US Air Force kept interceptors in Iceland till 2006, and still will fly to Iceland on occasions.
http://en.wikipedia.org/wiki/Military_of_Iceland
Just a comment of Iceland relations with the US. Technically Iceland is closer to North America then Europe, but that includes Greenland and New Foundland before you get to the actual North Amerian Continent.