USPS 2016 Holiday Domestic Shipping Deadlines
USPS Mail-by Dates (US Services)
Dec. 20 – First-Class Mail
Service for standard-sized, single-piece envelopes and small packages weighing up to 13 ounces with delivery in 3 business days or less.
Dec. 21 – Priority Mail
Domestic service in 1, 2 or 3 business days based on where the package is mailed and where it’s being sent, variety of flat-rate options.