Santa was still over the western Pacific when the calls started coming at 4 a.m.
By 10 a.m., 14,000 children had dialed the North American Aerospace Defense Command or reached out through email to get the latest update on his flight - a doubling over 2012.
The pace at Peterson Air Force base was frantic, but all had smiles at the command center where scores of volunteers gathered to keep the world alerted to the sleigh's journey.
"It's magical," said volunteer Jane Guthrie, a veteran of two years in the tracking business.
"A lot of them want to know if we need their address," she said.
While many of the calls came from Asia early in the day, the volume increased as East Coast kids got out of bed.
The magic of Christmas spurs a lot of questions from eager youth.
"I just fielded a chimney question," said Air Force Maj. Gen. Jeff Newell, a rookie tracker who serves as NORAD's top planner.
The number of brick chimneys built into American homes has fallen precipitously since air defense experts in Colorado Springs took the first Santa-tracking calls on Christmas Eve, 1955.
But trackers, volunteers using equipment donated by corporate sponsors, have gotten wise to the ways of Santa over the decades.
Volunteer Andy Miles disposed of a chimney call easily.
"I wouldn't worry about that," he told a chimney-less child. "I'm sure Santa can get in."
Simple explanations are best when dealing with the true-believers, he explained.
"You've got to think on your feet and a touch of magic always works," he said.
Through Christmas Eve, the command expected about 1,200 volunteers to help callers. They expected to be busy, topping the record of 114,000 calls set in 2012.
To deal with a local tradition that has become a worldwide event, the command has volunteers who speak several languages.
Canadian Forces Brig. Gen. Guy Hamel was hoping to use his French language skills.
"I'm waiting for the children from Quebec to call," he said.
In between questions on the lists, NORAD trackers have access to neither naughty nor nice, there were lots of smiles at the command center.
Air Force Col. Jeff Yocum said it is one of the best things he's done in the military.
"In terms of satisfaction, it's right up there."