The earliest religion coexisted with the first humans and was not founded. The entire ancient world possessed the original traditions of the Creation, the existence of the human soul and the afterlife, etc.
One thing that researchers agree upon is that mankind has always believed in a Higher Power. Archaeology has shown that no ancient society ever existed that did not believe in the supernatural.(See: Can you show me that God exists?)
Based upon a massive worldwide study of the most ancient inscriptions and the earliest levels of civilization, Dr. Wilhelm Schmidt (in his twelve-volume Der Ursprung Der Gottesidee) concluded that the original belief was monotheistic; a belief in One God (see footnote 1, below). It was a simple belief in the Creator (Dyeus Pater; Sky-Father) with no imagery of any kind. It gave way relatively quickly to polytheism and idolatry, but its traces could still be seen by the careful researcher, just as (for example) Proto-Indo European has left indelible marks within the later languages. Other traditions also are traceable worldwide, such as the religious significance of the number seven, and the immortality of the soul.
The process by which the awareness of One God gave way to a belief in many gods, has been described by Scandinavian researchers (see footnote 2) as splitting ("Gottespaltung"): the people gradually viewed God's attributes of truth, righteousness, fertility etc., as separate from Him, and afterwards personified and worshiped the attributes themselves, until God was largely forgotten.
According to Jewish tradition also, (Rashi commentary, Genesis 4:26), monotheism is more ancient than polytheism. Maimonides (see footnote 3, below) describes the process by which polytheism began: "A couple of centuries after the Creation, mankind made a great mistake. They said that since God had created the stars and spheres and placed them on high, accordingly it is fitting for people to praise and glorify them and to treat them with honor. They perceived this to be the will of God, that people should magnify and honor the stars. They began to praise and glorify them with words, and prostrate themselves before them, because by doing so, they would (according to their false conception) be indirectly honoring God too."
This descent into polytheism contributed to the weakening of any sense of religious belief and was also used as justification for excessive and licentious behavior, since the caprices which were narrated concerning the idols were adopted as an excuse to imitate their putative actions. See: Cruelties of the polytheists.
It was the original belief which Abraham reinstated through his teaching of ethical monotheism.
Footnotes:
1) Albright, "From the Stone Age," p.170; and J.A. Wilson, "The Culture of ancient Egypt," p.129. Also Baron, "A Social and Religious History," vol. I, p.44 and 311. Also James Meek, "Hebrew Origins," p.188, quoting Langdon, Lagrange and John Ross. Also Martin Nilsson, Handbuch der Altertumswissenschaften, 2nd ed., p.61, 141, 220 and 394.
2) G. W. Anderson, in "The Old Testament and Modern Study," p.287. Also Friedrich Baethgen, in Beitraege zur Semitischen Religionsgeschichte, p.288. Also Pallotino, "The Etruscans," p. 158 and 167.
3) See the full quote from Maimonides, in: "How did polytheism start?"
The first established religion in India is Hinduism. The second came hundreds of years later which is Buddhism which was proposed by Ghandi.
The earliest religion in North America was shamanism.
Yes, the earliest religion is shamanism.
Christianity
The earliest religion in society was animism.
Hinduism is the earliest trace of religion in India.
No, the religion of Islam was established by Prophet Muhammed.
Jesus and all the earliest disciples were Jews.
Probably Hinduism.
18th century
Animism
Atheism was never established, as it is not a religion.