US Post Office is located at 421 W Riverside Ave # 103, Spokane, WA. This business specializes in Post Offices. US Post Office is open Mon, 9am-4:59pm; Tue, 9am-4:59pm; Wed, 9am-4:59pm; Thu, 9am-4:59pm; Fri, 9am-4:59pm; Sat, Closed; Sun, Closed and accepts American Express, Discover, Mastercard and Visa.