US Post Office is located at 311 Centre St, Sullivan, NH. This business specializes in Post Offices. US Post Office is open Mon, 8am-4:59pm ; Tue, 8am-4:59pm ; Wed, 8am-4:59pm ; Thu, 8am-4:59pm ; Fri, 8am-4:59pm ; Sat, 8am-11:59am ; Sun, Closed. and accepts American Express, Discover and Visa.