Williamstown Post Office
613-347-2641
Monday - 9:00 AM –12:30 PM & 1:30 PM–5:00 PM
Tuesday - 9:00 AM –12:30 PM & 1:30 PM–5:00 PM
Wednesday - 9:00 AM –12:30 PM & 1:30 PM–5:00 PM
Thursday 9:15 AM –12:30 PM & 1:30 PM–6:00 PM
Friday 9:00 AM –12:30 PM & 1:30 PM–5:00 PM
19688 Warren Street
The Williamstown Post Office would like to remind you to include your PO Box number on all your incoming correspondence to ensure your mail arrives.