Here's a map of what states allow open carry, it is definitely more than you imagined.

https://opencarry.org/maps/map-open-carry-of-a-properly-hols...

and here's the Wiki article for concealed carry in each state

https://en.wikipedia.org/wiki/Concealed_carry_in_the_United_...

and a useful guide for state by state reciprocity of concealed carry permits.

https://www.usconcealedcarry.com/resources/ccw_reciprocity_m...