"We expect 50 million cards, letters and packages right here in the greater Los Angeles area," said Richard Maher, a USPS spokesman.
Nationwide, that number adds up to more than 800 million items, a jump of more than 40 percent over a usual day.
With holiday countdown underway, there are a lot of late mailers with crossed fingers.
"I'm really late in the process and I hope they get there," said Newport Beach resident Ron Siegel about the 40 packages he was sending.
But don't expect the lines at the local post office to vanish anytime soon.
"Every day is a busy day for the post office," said letter carrier Angel Baker. "It's been crazy for the past week or so. Through the first of the year it will probably be busy."