US Post Office is located at 347 Main St, Kewaskum, WI. This business specializes in Post Offices. US Post Office is open Mon, 9am-5pm ; Tue, 9am-5pm ; Wed, 9am-5pm ; Thu, 9am-5pm ; Fri, 9am-5pm ; Sat, 9am-11am ; Sun, Closed. and accepts American Express, Discover and Visa.