It's a question that's been asked since the 1823 poem, "Twas The Night Before Christmas" put reindeer power in Santa Clause's delivery service, but the question is always answered in terms of every child.
Leaving no child behind gives us a Santa whom according to Gizmodo, would have to at all times travel at 650 miles per second, which you can read about here, and is summed up by their own words, "If Santa ever DID deliver presents on Christmas Eve, he's dead now."
However, dead Santas make children sad, so we're going to see how many, if any children Santa can get presents to without dying. We start things off with Santa's sleigh, a hefty 1850 pounds empty, or an even ton with a 250 pound Santa at the helm.
Two average reindeer being 600 pounds, and pulling 1200 pounds each can do this handily, but Santa has a payload, about 60,000 tons based on a data dump from NORAD on Business Insider. To get all that moving is still possible. Santa just needs 100,000 reindeer to get his sleigh along, not aloft. There's no cheating this Christmas.
Now Santa can set off from his industrial complex in the north pole, ready to bring smiles to the kids of the nearest settlement with kids in Longyearbyen, Svalbard Norway.
He has about 32 hours of Christmas to burn thanks to time zones, and with fully harnessed reindeer topping out at 15 miles per hour, he'll be spending 19 of those getting to the edge of Longyearbyen, and because his reindeer, linked up in the traditional manner will stretch for 57 miles, Santa himself will be in town four hours after his reindeer. That gives him nine hours to deliver Christmas.
At about 6 square miles, Longyearbyen might not be breaking any records outside its latitude, but every one of those miles is packed with 10.7 children, 386 overall.
Counting all the numbers we have except the 57 miles of Nordic venison, Santa can can drop gifts off for the whole of Longyearbyen in two hours and 20 minutes. His deer aren't included because to put Santa in town, they would have to be 47 miles outside the next closest town, Barentsburg.
Here, with just seven hours to spare, Santa can spend the next nine minutes dropping off presents to 90 kids before heading out to mainland Europe.
The closest city to Barentsburg is Tromso Norway, about 586 miles from Svalbard, but even discounting the fact that it would take 40 hours to get there by sled, that distance is covered in liquid ocean. Svalbard is where Santa's mission starts and ends, providing just 472 children with 59,999 tons of gifts, so if you want to meet the man, you'll have to move to Svalbard.