how long does us postal priority mail take usually ranges from 1 to 3 business days for domestic deliveries. USPS Priority Mail is designed to be fast and reliable, offering included tracking and up to $100 insurance coverage. Delivery time varies slightly based on the origin and destination zip codes, as well as weather and mail volume. Unlike First-Class Mail, Priority Mail supports packages up to 70 lbs and includes free USPS-branded shipping supplies. For time-sensitive documents or parcels, Priority Mail is often the preferred balance of cost and speed, though it is not guaranteed overnight unless upgraded to Priority Mail Express.