USPS

The U.S. Postal Service is the only delivery service that reaches every address in the United States: 155 million residences, businesses and Post Office Boxes. With more than 31,600 retail locations and more than half a million employees, the Postal Service is one of the nation’s largest employers. Everyone living in the United States and its territories has access to postal products and services and pays the same for a First-Class postage stamp regardless of their location.