Is the United States talked about in the book of Revelation?
Not that I know of!
I suppose the question means, "specifically mentioned" or "in one of the symbols it's really there," not "When the whole world is talked about is the United States included?" because obviously it is.
I have lots of questions about how the symbolism of Revelation works, but in my understanding there aren't specificities like that in the book of Revelation.
These are pretty broad, sweeping indictments of mankind in our rebellion against God. And the kinds of judgments that are coming are so huge that it isn't particular nations that are highlighted so much as nations that are in rebellion against God, namely, all of us in all the different nations who are in rebellion against God. And hopefully we're not in that number.
The main point of the book of Revelation is that Christ wins in the end. And that to have your name written in the Lamb's Book of Life, so that you don't get any mark of belonging to any beastly power, is absolutely essential.
Those who have their names written in the Lamb's Book of Life are enabled not to give in to any beastly, antichrist power that comes along.
And that's the most important thing for us individually: that we love Christ so much that we defeat Satan by the word of our testimony and by the blood of the Lamb, and thus find ourselves on the right side of the Lamb when he comes when others are going to say, "O rocks, fall upon me!" because they can't bear to look upon the wrath that will stream forth from the face of the Lamb of God when he comes the second time.