The First Amendment to the U.S. Constitution says that everyone in the United States has the right to practice his or her own religion, or no religion at all.
Our country's founders -- who were of different religious backgrounds themselves -- knew the best way to protect religious liberty was to keep the government out of religion. So they created the First Amendment -- to guarantee the separation of church and state. This fundamental freedom is a major reason why the U.S. has managed to avoid a lot of the religious conflicts that have torn so many other nations apart.
Learn more here about your right to express your religion and belief and be protected from discrimination.