Home Postcode finder QLD Highland Plains Highland Plains postcode QLD Highland Plains is a locality in Queensland covered by postcode 4454. Postcode 4454 State or territory Queensland (QLD) Region Toowoomba Region Add a free Highland Plains business listing Be the first listing in Highland Plains Common questionsWhat is the postcode for Highland Plains?Highland Plains, QLD has the postcode 4454.What state is Highland Plains in?Highland Plains is in Queensland (QLD).Does postcode 4454 cover more than one suburb?Yes. Postcode 4454 covers 11 localities, so the postcode alone does not identify Highland Plains. Browse other postcodes in Queensland, or widen the search to every Australian postcode.