As of 2008, a majority of americans identified as muslim. christian. jewish. buddhist.

Christian

Explanation:

In 2008, the majority of the Americans identified themselves as Christians. The Christians far outnumber any other religious group in the country, so much so that all the others put together don't even make one quarter of the Christian population. There are divisions in the Christians though, as there are some that are of the Catholic branch, some are Protestants, Orthodox, Evangelists, Adventists, Lutherans etc. The differences are far less than the similarities, and they are all part of the same religion. It is interesting in the USA that the atheism is not kicking in as much as in the other Western countries.