I'd use "at the back (of the room)", for example -- "Tom likes to sit at the front of the classroom so that he can see the board, better, but Peter likes to sit at the back".
So perhaps Péter is standing at one end of a big meeting room, with television crew at the front near him, reporters in the middle, and politicians at the back.
Ah yes, thank you. So it seems to be pretty equivalent to "in the back" as I understand it, and that's just what hátul, and conversely elöl, express. A relative spot within a certain area, like a room.
"Tamás elöl szeret ülni az osztályteremben, Péter pedig hátul." - "Tom likes to sit in/at the front of the classroom, but Péter prefers the back."
"In back" is actually okay English, but it generally means "behind" rather than "at the back of a space." Example: "She and spoke in the back." <--- There is a room, and in the back part of that room, she and I spoke. "There is parking in back." <--- BEHIND the building, there is parking. In fact, in older English you could just say "back" to refer to behind something:
"Back the clock tower, children played."
But this is much less common nowadays.
"Peter sees politicians in the rear." ? I see them as rear ends but that is beside the point.
Ah, and here's the trick: hátul does not mean "behind" at all. "Behind" is expressed with the postposition mögött: "Péter politikusokat lát egy épület mögött." - "Peter sees politicians behind a building."
Hátul, on the other hand, means "in the back". In the back of a group or of a room, or whatever you can be in the back of. The difference is that with hátul you're still within the specified area, and with mögött you're outside of it.