Post Office – Dungannon, Castlecaulfield – Opening Hours & Branch Details Post Office occupies a prominent position at 32 Main Street, approximately 2.81 miles west of the centre of Dungannon. Patrons can easily travel here from Stakernagh, Reaskcor, Glasmullagh, Mullaghacreevy, Granville, Castlecaulfield, Drumhirk and Annaghmakeown. Today (Friday), business times start at 10:00 am and end at 1:30 pm. This page will provide you with all the information you need on Post Office Dungannon, Castlecaulfield, including the working hours, address particulars, customer experience and more info.