Home Postcode finder NSW Killingworth Killingworth postcode NSW Killingworth is a locality in New South Wales covered by postcode 2278. Postcode 2278 State or territory New South Wales (NSW) Region Hunter Add a free Killingworth business listing Be the first listing in Killingworth Common questionsWhat is the postcode for Killingworth?Killingworth, NSW has the postcode 2278.What state is Killingworth in?Killingworth is in New South Wales (NSW).Does postcode 2278 cover more than one suburb?Yes. Postcode 2278 covers 3 localities, so the postcode alone does not identify Killingworth. Browse other postcodes in New South Wales, or widen the search to every Australian postcode.