What nations hold atheism as a predominant faith?

At this time I don't believe there are any countries that actively support atheist as a predominant 'faith'. However, the United States of America has no official religion.

Answer:

The governments of many countries are secular and religion has no official role in their government although their may be references to oaths and God in their constitutions and rituals, these would include China, Russia, America, Canada, etc. Secular should not be confused with atheist. In contrast some countries are openly theocratic where religion is blended with the government such as the Vatican, many Arabian countries and so on. Theocracies are not atheist. Some are a mixture where, like Great Britain, the head of state is also the head of the government but the day to day rule is mostly secular. Others like China have encouraged their citizens to nort go to church and still others (North Korea) have substituted a state sponsored way of life (Juche) as a substitute for religion.

However as no country has bothered to make it part of their constitution or founding principles that there is no deity (a requirement for atheism) so there are no atheist countries.

The populations of the world's countries are mixed as far as the religious positions of their citizens ranging from several European countries like Sweden which have a high percentage of atheists to the Vatican which is almost all Christian.