Hey @Jim_Pederson,
that is probably very difficult to set up as every country (and even just states) have different public holidays.
What is available right now is that you can set the start of the week via profile settings
And in the timeline view when you shift your due dates for dependencies you can set it to avoid weekends
There are a bunch of feedback request threads you might be interested upvoting:
Now when you create project templates you can also tick the box to skip weekends
And for repeating tasks you can also set them up to tick the days to count and skip weekends this way but not business days per se as they are different everywhere.