A generally derogatory term for residents of Big Horn County, Wyoming. Counties in Wyoming are represented as the first number on a Wyoming license plate. Big Horn County is represented as the number "9."
"Why in the hell is this person driving 25 in a 45 mph zone? Ohhh, of course; it's a fucking Niner!"
"Wait, so you grew up in Big Horn County? Let me ask you something that has been pissing me off since I moved here four years ago; why do Niners drive so slow? There is no excuse for it!"