Home Postcode finder NSW Glen Oak Glen Oak postcode NSW Glen Oak is a locality in New South Wales covered by postcode 2320. Postcode 2320 State or territory New South Wales (NSW) Region Hunter Add a free Glen Oak business listing Be the first listing in Glen Oak Common questionsWhat is the postcode for Glen Oak?Glen Oak, NSW has the postcode 2320.What state is Glen Oak in?Glen Oak is in New South Wales (NSW).Does postcode 2320 cover more than one suburb?Yes. Postcode 2320 covers 30 localities, so the postcode alone does not identify Glen Oak. Browse other postcodes in New South Wales, or widen the search to every Australian postcode.