Addresses, Phone Numbers, and Business Hours for Post Offices in Sinai, SD.
About Post Offices
A USPS Post Office is a local branch of the United States Postal Service. In 1789, the USPS operated 75 Post Offices, and since then the USPS has opened thousands of Post Offices around the country. Today, USPS Post Offices sort, process, and deliver mail, provide USPS services to customers, and offer a range of other services, including passport services.