Domestic send-by dates for expected delivery before Dec. 25th*:
USPS Retail Ground™ // December 14
First-Class Mail® // December 20
Priority Mail® // December 20
Priority Mail Express® // December 22

*Actual delivery date may vary and is based on origin, destination, Post Office acceptance time and other conditions.
To learn more and find USPS Holiday resources, visit: http://about.usps.com/holidaynews/