The Deists

Like atheists, deists do not perceive a God around. But the deist does see evidence to suppose that the deity once was, whereas the atheist sees no such thing. 

Deists are those who reason that the laws governing nature presuppose a supreme lawmaker or a God, but they neither seek to define that deity nor believe that this God is presently involved in nature. (The Creator of the world and its natural laws takes no further part in their functioning.)

Since deists do have a form of god-belief (on purely rational grounds), are they "believers" or "freethinkers"? Actually deism represents a skepticism not far removed from agnosticism.  Its spirit of criticism aims at the nature and content of traditional religious beliefs integral to Christian, Islamic, Jewish, etc. doctrine, substituting for them a rationalistic naturalism. [The early development of deistic thought in England in the late 17th century was, for the most part, an intellectual movement critical of revealed religion.] 

Deists reject claims of supernatural revelation and place no reliance on doctrinal authority. Their life pattern is  distinctly atheistic (without the deity) since, even as they discuss ethics, there is no acceptance of, or belief in, or appeal to, divinely revealed rules for ethical conduct. Some dictionaries follow their "deist: a believer in deism" entry with "syn. see atheist."

There may not be as many deists in the United States now as there were in the days of the founding fathers, but deism remains an important category of freethought. (It is vital to historical understanding of Enlightenment thinking and development of the western world in the 17th and 18th centuries.) Some U.S. deists belong to organizations like the American Ethical Union, where the focus is on ethical growth and development.

Atheists Secular Humanists