The program launched online last Monday, and within that week, the website has run out of letters.
The goal of the campaign is to give kids who may not be able to otherwise, the happy holiday they deserve.
But the postal service wants to help more children and their families.
They want to encourage more deserving children to write, the postal service has a letter-writing kit with templates that can be accessed on the Operation Santa website.
Letters are addressed to:
123 Elf Road
North Pole, 88888
All letters should be postmarked by Dec. 14.
The idea began in 1912 with Postmaster General Frank Hitchcock, who authorized local Postmasters to allow postal employees and citizens to respond to the letters. The program eventually became known as Operation Santa.
To celebrate 107 years, USPS launched a new website for Operation Santa featuring letters from children across the country.
This year letters from Chicago along with 14 other cities will be displayed on the website through the holiday season.
Residents in Chicago will have a choice of browsing and adopting letters to Santa online or in person.
Letters for Operation Santa can be sent
123 Elf Road, North Pole 88888
For people who wish to adopt some of the Christmas letters, find a post office that offers "Label Broker" as an on-site service to send the gift.
For more information on how to get involved visit the USPS FAQ.
For more information on how to adopt a letter visit uspsoperationsanta.com