In BrambleClan, the den next to the ginger cat with black stripes (Ashtail) which is next to where Amberstar, Moss-shadow and Duskfall are. In FireClan, the same place where Crescentsomething and her kits are, however, there is a glitch now that she and her kits don't move so they're literally sitting on them, so probably wait for her kits to become apprentices before having kits in FireClan. In SunClan, by the boxes. In FallenClan, the first den you see.