Post Office – Newton Stewart, Main Street 3 – Opening Hours & Branch Details Post Office is found in an ideal position on Main Street, about a 14.17 mile drive south-west of the centre of Newton Stewart (near to Town Hall). This branch is glad to provide service to patrons within the districts of Maryport, Stoneykirk, Castle Kennedy, Boreland, Balgowan, Dunragit and Glenluce. It will be closed the whole day (Friday). This page will give you all the information you need about Post Office Newton Stewart, Main Street 3, including the business hours, branch address, contact number and further details.