also: むにんのきょう
expression, noun
uninhabited region; desolate area
Refers to a place where no people live or are present; often used in literary or descriptive contexts.
その探検家は無人の境を何日も歩き続けた。
The explorer walked for days through the uninhabited region.
無人 is a more common word for 'uninhabited' or 'unmanned'; 無人の境 is a set phrase emphasizing the desolate, uninhabited nature of a place.
Compound of 無人 (uninhabited) + の (possessive particle) + 境 (boundary, region). The exact historical derivation is uncertain, but it is a classical-sounding phrase.