back of (the) beyond
Very distant or remote. His new house is really back of beyond—it will take us hours to get there. This private island resort is really back of the beyond.
back of beyond
Extremely remote. For example, John's about to move to some tiny island, truly back of beyond. This term, used as a humorous exaggeration, relies on the meaning of beyond (or the beyond) as "a distant place, beyond human experience." [Early 1800s]
back of beyond
A place that is remote or unsophisticated.