Eleusis.
At her sanctuary in Eleusis.
Olympus
the greek goddess Demeter was born on the earth, no known exact location but she was put there to help the farmers plant and yield and those sort of things
ask percy jackson
You do know that she's not real, right? She can't have a "last known location" if she never existed.
No, the Greek goddess Demeter does not have a last name, she does have titles and epithets.
She is a Greek goddess so her last location would be Ancient Greece.
hell
pooooop
The sea.
Demeter's worship is known as the Eleusinian Mysteries.
He had no last known location because he was not real. Even if he were, he was a god, and thus, omnipresent.