SASS - The Single Action Shooting Society, the governing body for CAS
CAS City - a great site with terrific links and vendors.  Home of the CAS-l Mailing List, a must see.
Nearby Cowboy Shooting Clubs
Territorial Marshals -- Arcadia, OK (Oklahoma City) A great place with great people where most of us shoot on the fourth Sunday -- Home of LandRun.
Indian Territory SASS - Coweta, OK (Tulsa) -- They mosey down to whip up on us in OKC.  They shoot on the Second and Fifth Sundays.
Tater Hill Regulators - Tulsa.  They shoot on the Third Sunday.
Cherokee Strip Shootists - Stillwater.  They shoot on the First Sunday.
A Little Farther, Cowboy Shooting Clubs
Lone Star Frontier Shooting Club - South of Fort Worth.  This is a great group and hosts Roundup.  They shoot on the Second Saturday and the Last Sunday.
Comanche Valley Vigilantes - Glen Rose, Texas   This is the home of The Showdown at Buck Creek.  They shoot on the Third Saturday and Sunday each Month.
Good Friends
Lawton-Fort Sill Rifle and Pistol Club, Inc.This is a good group, shoots at the Fort Sill at the foot of Medicine Bluff I
True Grit  - Dardanelle, in Yell County, Arkansas.  They shoot on the Fourth Sunday.
Canadian River Regulators - Clarendon, TX (this side of Amarillo) - They shoot at the Bar H Dude Ranch on the Second Saturday.
Badlands Tactical Training Facility  -  Want to shoot long range?  This is the place to learn.  You would not believe the list of client.  Check it out.