There are several in St. Louis. You can find a lot of them on meetup.com. I also coordinate a monthly happy hour for informal networking (no agenda or anything). Details are here:
Check biggerpockets.com/events to search for more in the area!
@David Orrick you need to check out JeffCo REI. They meet in Herculaneum which is not too far from you. Great group. PM me if you want more details.