> In the United States, employers with more than 100 full-time, non-probationary employees must provide 60 days notice of most planned layoffs[0]

I'm not sure how that works, because I've been at a US company that did layoffs and they suddenly announced the layoff saying the impacted employees would be notified within a day.

Except for France and other European countries, where they announced the beginning of the process meaning the number and list of people let go wasn't decided yet (it would have been illegal).