Which countries do not feature mosquitoes?
According to India.com, Chris is right and Iceland has been declared mosquito free. 

The science behind this is quite interesting and there are various hypotheses regarding as to why Iceland doors are shut to mosquitoes. The most preferred hypothesis by scientists, according to New York Times is >>


  When mosquitoes lay eggs in cold weather, the larvae emerge with a
  thaw, allowing them to breed and multiply. Iceland, however, typically
  has three major freezes and thaws a year, creating conditions that may
  be too unstable for the insect’s survival.