Home Postcode finder SA Mount Gambier West Mount Gambier West postcode SA Mount Gambier West is a locality in South Australia covered by postcode 5291. Postcode 5291 State or territory South Australia (SA) Region SA Outer Suburbs Add a free Mount Gambier West business listing Be the first listing in Mount Gambier West Common questionsWhat is the postcode for Mount Gambier West?Mount Gambier West, SA has the postcode 5291.What state is Mount Gambier West in?Mount Gambier West is in South Australia (SA).Does postcode 5291 cover more than one suburb?Yes. Postcode 5291 covers 34 localities, so the postcode alone does not identify Mount Gambier West. Browse other postcodes in South Australia, or widen the search to every Australian postcode.