Here is the one and only reference to the Nephilim in The Urantia Book:

77:2.3 The postrebellion era on Urantia witnessed many unusual happenings. A great civilization—the culture of Dalamatia—was going to pieces. “The Nephilim (Nodites) were on earth in those days, and when these sons of the gods went in to the daughters of men and they bore to them, their children were the `mighty men of old,’ the `men of renown.'” While hardly “sons of the gods,” the staff and their early descendants were so regarded by the evolutionary mortals of those distant days; even their stature came to be magnified by tradition. This, then, is the origin of the well-nigh universal folk tale of the gods who came down to earth and there with the daughters of men begot an ancient race of heroes. And all this legend became further confused with the race mixtures of the later appearing Adamites in the second garden.

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And – you will also want to read about the origins of these superhuman beings that are referred to as “nodites” in order to understand a key piece of earth’s history that still affects our world today. This important event was the first revelation of God to mankind over 500,000 years ago.

Please click here to read more about how the Nephilim came to be.

Read about these beings in the beginning

And read about how they were organized in the beginning

Finally, I recommend you read all of Paper 66, from which the above references are taken, so you will then have the proper context to understand fully about these beings.

I realize that you asked only about the Nephilim, but in order to understand the truth about them, we have to understand other factors and other events that will serve to really help us grasp what happened. These events from Earth’s history, including these beings, are part of revealed information found only in The Urantia Book.

It is of great importance that we learn the facts of our long-ago history in order to properly go forward in our troubled world. Once we understand the factors that contributed to the decline of spirituality and truth in our world, we are then able to identify and overcome the remnants of the disastrous rebellion that Lucifer created all of those thousands of years ago, and into which our trusted Planetary Prince, Caligastia, led our unsuspecting world.

His crime was so great that the revelators of The Urantia Book have designated him as “the devil.”