Home Postcode finder NSW Mountain Lagoon Mountain Lagoon postcode NSW Mountain Lagoon is a locality in New South Wales covered by postcode 2758. Postcode 2758 State or territory New South Wales (NSW) Region Nepean Add a free Mountain Lagoon business listing Be the first listing in Mountain Lagoon Common questionsWhat is the postcode for Mountain Lagoon?Mountain Lagoon, NSW has the postcode 2758.What state is Mountain Lagoon in?Mountain Lagoon is in New South Wales (NSW).Does postcode 2758 cover more than one suburb?Yes. Postcode 2758 covers 11 localities, so the postcode alone does not identify Mountain Lagoon. Browse other postcodes in New South Wales, or widen the search to every Australian postcode.