GENESIS 2:14

[NKJV]

The name of the third river is Hiddekel; it is the one which goes toward the east of Assyria. The fourth river is the Euphrates.

[AKJV]

And the name of the third river is Hiddekel: that is it which goes toward the east of Assyria. And the fourth river is Euphrates.

These two Rivers differed from the first two in preceding verses by these two Rivers not compassing or surrounding any land as if being in love with a land unlike the first two. Rather these Two Rivers just cut  through all the lands on their parts, forming partial borders/boundaries to various lands but made none island. E.g. Tigris river was partial East Border to Assyria, and Euphrates was partial Border/Boundary to Israel's Promised Land.

Moreover, these two Rivers, Hiddekel (Tigris) and Euphrates, were the most spiritually significant rivers on earth outside Eden, having roles in Revelations and Visions. Therefore, they were referred to as the "Great River" in books of Revelation. Examples

[Daniel 10:4‭-‬7 AMP] — On the twenty-fourth day of the first month, as I was on the bank of the great river Hiddekel [which is the Tigris], I raised my eyes and looked, and behold, there was a certain man dressed in linen, whose loins were girded with [a belt of] pure gold of Uphaz. His body also was like beryl [with a golden luster], his face had the appearance of lightning, his eyes were like flaming torches, his arms and his feet like the gleam of burnished bronze, and the sound of his words was like the noise of a multitude [of people or the roaring of the sea]. And I, Daniel, alone saw the vision [of this heavenly being], for the men who were with me did not see the vision; nevertheless, a great panic overwhelmed them, so they ran away to hide themselves.

Four Angels were imprisoned and chained inside one of these great Rivers, Euphrates precisely; and it will take one of the Seven last trumpets of Angels and a voice of the Four Horns of God's Altar to release those four Angels trapped/tied at the greatest River, Euphrates. As it is written,

[Revelation 9:14-14] — "And the sixth angel sounded, and I heard a voice from the four horns of the golden altar which is before God, Saying to the sixth angel which had the trumpet, Loose the four angels which are bound in the great river Euphrates."

The Book of Jeremiah was bound with a stone and cast into the great River Euphrates from where it will not rise up again, as a prophecy that Babylon shall fall and not rise again. Written thus:

[Jeremiah 51:63‭-‬64 GNT] — Seraiah, when you finish reading this book to the people, then tie it to a rock and throw it into the Euphrates River and say, ‘This is what will happen to Babylonia—it will sink and never rise again because of the destruction that the Lord is going to bring on it.’” The words of Jeremiah end here.

The greatest of the Four Rivers is the great River Euphrates, which is the top Bible verse above was not even associated or connected to any land as Landmark. Euphrates did not need any land for identity, but remained as the remnant of the River from Eden after the other three branched off to their separate paths.

Great River Euphrates cannot be dried up by any natural forces, unless by the Bowl of God's Wrath poured into that River to dry it. And the day that great River Euphrates shall be dried up shall be day to begin Armageddon War between Christ and Anti-Christ.

[Revelation 16:12‭-‬16 NKJV] — Then the sixth angel poured out his bowl on the great river Euphrates, and its water was dried up, so that the way of the kings from the east might be prepared. And I saw three unclean spirits like frogs coming out of the mouth of the dragon, out of the mouth of the beast, and out of the mouth of the false prophet. For they are spirits of demons, performing signs, which go out to the kings of the earth and of the whole world, to gather them to the battle of that great day of God Almighty. “Behold, I am coming as a thief. Blessed is he who watches, and keeps his garments, lest he walk naked and they see his shame.” And they gathered them together to the place called in Hebrew, Armageddon.