Holiday Calendar

Hello and happy new year!

I wrote a stored proc that basically aggregates some data based on how many Monday's, Tuesday's, Wednesday's etc in a current month (date range parameters). The proc works great, however I need to filter out holidays to get the correct number of days for the divisor.

My question is... What is the best way to approach this? I was considering creating a holiday table and manually entering holidays up until 2020, but that seems like a rookie move.

What are some dynamic approaches to this?
Any help is greatly appreciated.

Dave