Where does Isaiah chapter five take place and when?

Answer 1

It refers to the land of Israel, and was partially-fulfilled in the past in 586Bc and 722BC, but is yet to be completely fulfilled at the return of Jesus Christ. Dr John MacArthur in his "The MacArthur Study Bible" says :

This extended discourse begun at [Isaiah] 2:1 [is] ....a comparison of God's people [ie nation of Israel] to a vineyard which He cultivated, but which did not bear fruit.

On verse 5:-

(Isa 5:5 And now I will make known to you what I will do then to My vineyard. I will take away its hedge, and it will be burned. I will breach its wall, and it will become a trampling ground.)

As punishment for her unfaithfulness, Israel became desolate and accessible to any nation wishing to invade her, such as happened in the Babylonian invasion of 586BC, and will happen repeatedly until her national repentance at the Second Coming of Christ.

On verse 26:-

(Isa 5:26 And He will lift up a banner to distant nations, and will hiss to them from the ends of the earth; and, behold, it shall come with swift speed! )

Principal among the nations God would bring against israel were:

1) Assyria which conquered the northern kingdom in 722BC

2) Babylon which completed its invasion of Jerusalem in 586BC.