Post Office – Newcastle, Dundrum – Opening Hours & Branch Details Visit Post Office at 12 Main Street, approximately a 176.23 mile driving distance west from the centre of Newcastle. This branch is an excellent addition to the local businesses of Castlewellan, Dundrum, Moneylane, Ballykinler Upper, Murlough Lower, Cloghram and Ballig. Drop by today (Friday) from 7:00 am – 10:00 pm. Here you will find the specifics for Post Office Newcastle, Dundrum, including the opening times, local navigation, direct phone and additional essential information.