How to see how many people can attend a wedding before booking?

I have been looking at a lot of different venues to hold a wedding. There are some that hold 50, and others that hold 100+, and they are all pretty much in different cities from eachother.

For example:
If I had a choice between a venue in Spokane Washington that can hold 100-200 guests and
A venue in Portland Oregon that can only hold 50 guests.

Because I wouldn’t want to book the one in Spokane that may be a little more expensive when no one will come…..
or book the one in Portland and have too many people come.
I didn’t know if there was a way to find out who can actually come to each one before I book a place and let everyone know where the wedding will actually be held at….like maybe in a wedding announcement before I send out the actual invitation? How would I word it? Has anyone else ran into this problem and found a solution?