Archon St. Louis is a speculative fiction genre convention based in...wait for it...Collinsville, IL. It's just over the border from St. Louis, Missouri. The con is typically held at the Gateway Convention Center and the Doubletree Hotel.
I just arrived home from ArchonSTL a few hours ago. This is the 41st year of the convention, so they're doing things right. Twisted_Missus and I like to attend this convention because it's a relaxing, family-friendly event. It's the only con where we don't even bring any books to sell. We go to sit on discussion panels and to see some friends. This year, the toastmaster was my friend Bryan Thomas Schmidt, a Hugo-nominated editor and a prolific anthology cat herder and author. We enjoy riffing off of each other during the panels, so I get to be the comedy relief.
While the focus is on science fiction and fantasy, there are general speculative fiction panels like horror and other topics. The convention makes things easy for the convention-going crowd by grouping the panels and events into different tracks. The Mrs. and I were both on panels from the author craft track, plus she was on several costuming and cosplay panels. She's more versatile than I am, after all.
I was pleased that the programming staff added in some horror panels again this year. I was on one titled "Writing Modern-Day Monsters", where we discussed what a modern-day monster is (or can be) and how to write an effective one. My fellow panelists were Setsu Uzume and Michales Joy. Monsters ranged from the usual Kaiju friendlies to serial killers to more traditional creatures that go bump (and sometimes grind) in the night.
ArchonSTL is also one of the big costuming competitions, which attracted my wife to the con originally. She did reveal a new costume and cosplay that had a lot of attendees getting stumped because they knew the character but couldn't place her, especially with her iconic purple wig. She went as Lieutenent Ellis from the 1969 British science fiction television show UFO, specifically the outfit from Moonbase Alpha. We saw a lot of amazing cosplayers, including a traditional Japanese devil with very loud jingly bells, horns, and a tongue longer than most of my neckties.
It's a mid-sized local con, so you won't feel lost in a crowd of 120,000 of your closest friends in one building. This year their attendance was 2,300. The convention staff are some of the friendliest folks in the convention game, and they do take good care of their pro guests. The VIP green room was always stocked with amazing food, including a hot breakfast every morning, Philly cheesesteaks for lunch and beef stew for dinner on Saturday. I know I gained six pounds from the tasty foods that they had available.
If you're looking for an autumn convention in the middle of the country, I'd recommend ArchonSTL. The con is usually in late September or early October, and their website is at http://www.archonstl.org.