Home Postcode finder WA Brown Hill Brown Hill postcode WA Brown Hill is a locality in Western Australia covered by postcode 6431. Postcode 6431 State or territory Western Australia (WA) Region Wa Subs 1 G Flds Add a free Brown Hill business listing Be the first listing in Brown Hill Common questionsWhat is the postcode for Brown Hill?Brown Hill, WA has the postcode 6431.What state is Brown Hill in?Brown Hill is in Western Australia (WA).Does postcode 6431 cover more than one suburb?Yes. Postcode 6431 covers 13 localities, so the postcode alone does not identify Brown Hill. Browse other postcodes in Western Australia, or widen the search to every Australian postcode.