overnight mail usps

overnight mail usps Overnight mail USPS refers to Priority Mail Express, the fastest service offered by the United States Postal Service, guaranteeing next-day delivery to most U.S. addresses, including weekends and holidays in eligible locations. This service includes tracking, insurance up to $100, proof of delivery, and flat rate options for envelopes and boxes. Overnight mail USPS is ideal for sending urgent legal documents, medical supplies, or last-minute gifts, offering peace of mind with guaranteed delivery by the following business day.