Um... Forgotten Realms is a campaign setting. So, in the Forgotten Realms series, they're in... Forgotten Realms.
Sorry I am really new to this whole Forgotten Realms / DnD thing. Your saying that Faerun and Ebberon are both part of the Forgotten Realms, and while stuff is happing in Faerun, other stuff is happening in Eberron? Cus If I remember correctly, at the end of the first campaign in Neverwinter Nights you come across that chick that looks just like Aribeth, but shes not... she says she is from some other realm...