Revelation 20  mentions a special 1,000 year period commonly referred to as the Millennial Reign. That chapter also mentions of an angel coming down from heaven. However, the Holy City does not come down until Revelation 21 . It makes me wonder if the Millennial Reign will take place in Heaven. The main reasons are:
- There is no mention of Millennial Reign taking place on earth.
- Where would the Millennial Reign be on earth if the Holy City has not landed on earth until Revelation 21.
But Premillennialists teach that this Millennial Reign will take place on earth. What is the Biblical or theological basis for their teaching?
 Revelation 20:1 - 6 ESV
Then I saw an angel coming down from heaven, holding in his hand the key to the bottomless pita and a great chain. And he seized the dragon, that ancient serpent, who is the devil and Satan, and bound him for a thousand years, and threw him into the pit, and shut it and sealed it over him, so that he might not deceive the nations any longer, until the thousand years were ended. After that he must be released for a little while. Then I saw thrones, and seated on them were those to whom the authority to judge was committed. Also I saw the souls of those who had been beheaded for the testimony of Yahusha and for the word of Elohim, and those who had not worshiped the beast or its image and had not received its mark on their foreheads or their hands. They came to life and reigned with Christ for a thousand years. The rest of the dead did not come to life until the thousand years were ended. This is the first resurrection. Blessed and holy is the one who shares in the first resurrection! Over such the second death has no power, but they will be priests of God and of Christ, and they will reign with Him for a thousand years.
 Revelation 21:1 - 3 ESV
Then I saw a new heaven and a new earth, for the first heaven and the first earth had passed away, and the sea was no more. And I saw the holy city, new Jerusalem, coming down out of heaven from Elohim, prepared as a bride adorned for her Husband. And I heard a loud voice from the throne saying, “Behold, the dwelling place of Elohim is with man. He will dwell with them, and they will be His people, and Elohim Himself will be with them as their Elohim