In the symbolic language of prophecy, mountains stand for nations or countries

The Babylonian Empire

Hark, a tumult on the mountains as of a great multitude! Hark, an uproar of kingdoms, of nations gathering together! The LORD of hosts is mustering a host for battle. Is. 13:4 

The Northern Tribes

For a voice declares from Dan and proclaims evil from Mount Ephraim. Jer. 4:15

Babylon taking Jerusalem

I looked on the mountains, and lo, they were quaking, and all the hills moved to and fro. Jer. 4:24

The Medes taking Babylon

“Behold, I am against you, O destroying mountain, says the LORD, which destroys the whole earth; I will stretch out my hand against you, and roll you down from the crags, and make you a burnt mountain. Jer. 51:25 

Restoration of Israel

“And you, son of man, prophesy to the mountains of Israel, and say, O mountains of Israel, hear the word of the LORD. Ezek. 36:1 

The Coming Kingdom of Messiah

. . . then the iron, the clay, the bronze, the silver, and the gold, all together were broken in pieces, and became like the chaff of the summer threshing floors; and the wind carried them away, so that not a trace of them could be found. But the stone that struck the image became a great mountain and filled the whole earth. Dan. 2:35

All the nations the Jews will return from

In that day they will come to you, from Assyria to Egypt, and from Egypt to the River, from sea to sea and from mountain to mountain. Mic. 7:12

God’s Judgment of the Nations

He stood and measured the earth; he looked and shook the nations; then the eternal mountains were scattered, the everlasting hills sank low. His ways were as of old. Hab. 3:6

The Political Forces that Oppose the Jews

What are you, O great mountain? Before Zerubbabel you shall become a plain; and he shall bring forward the top stone amid shouts of ‘Grace, grace to it!’” Zech. 4:7

The Kingdom of Satan

He said to them, “Because of your little faith. For truly, I say to you, if you have faith as a grain of mustard seed, you will say to this mountain, ‘Move from here to there,’ and it will move; and nothing will be impossible to you.” Matt. 17:20

The Coming New World Order, or the Kingdom of our God

And every island fled away, and no mountains were to be found; Rev. 16:20

Seven Mountains are Seven Kings

9 This calls for a mind with wisdom: the seven heads are seven mountains on which the woman is seated;  10 they are also seven kings, five of whom have fallen, one is, the other has not yet come, and when he comes he must remain only a little while. Rev. 17:9-10