On May 2, 2011, USCIS announced that they have fully implemented the Secure Mail Initiative (SMI), which uses the United States Postal Service’s Priority Mail with Delivery Confirmation to ensure that certain immigration documents such as permanent resident cards, travel documents, and employment authorization documents are delivered in a safe, secure, and timely manner. In addition to faster delivery (USCIS says that on average, documents sent through USPS Priority Mail should arrive two to four business days sooner than with first-class mail), one of the key benefits to the SMI is that USCIS customers will be able to track the status of their documents once they receive an approval notice.
The USCIS notices states that:
"Customers who receive notices of approval can contact USCIS’s Customer Service Center at 800-375-5283 to request tracking information for their documents. USCIS customer service representatives will provide customers with their USPS tracking number and current USPS delivery status."
"Customers should wait at least two weeks after getting their approval notice before calling for information regarding their cases. When requesting tracking information, customers must also provide information from the receipt notice they received when they submitted their initial application. After receiving the tracking number from the USCIS Customer Service Center, customers can track the delivery status by visiting the Postal Service website at www.usps.com and entering the USPS tracking number into the Track & Confirm field."