US Post Office is located at 21 Mill St, Millsboro, PA. This business specializes in Post Offices. US Post Office is open Mon, 8:59am-4:59pm; Tue, 8:59am-4:59pm; Wed, 8:59am-4:59pm; Thu, 8:59am-4:59pm; Fri, 8:59am-4:59pm; Sat, 8:59am-12:25pm; Sun, Closed and accepts American Express, Discover and Visa.