Which domestic mail service is recognized as the fastest?

Express mail is recognized as the fastest domestic mail service. It is designed for urgent deliveries and offers guaranteed overnight delivery to most locations, along with tracking features and insurance options. This service prioritizes speed, ensuring that items reach their destination as swiftly as possible.

In contrast, first-class mail is a reliable and cost-effective option for sending letters and lightweight packages, but it does not guarantee overnight delivery and may take 1 to 3 days for arrival. Priority mail, while quicker than first-class, typically delivers within 1 to 3 business days and is used for medium weight packages, but again, it does not match the speed and urgency of express mail. Standard mail, previously known as third-class mail, is the slowest option, primarily used for bulk advertising and promotional materials and not intended for time-sensitive shipments. Thus, express mail stands out as the fastest service available for domestic delivery.