You may trap privately owned land in the state of Missouri with the permission of the landowner and the purchase of a trapping permit. However, in cities with more than 10,000 inhabitants you may only use cage traps or dog-proof traps if you are within 150 feet of any residence or occupied building. Check your local ordinances before setting any type of trap within city limits.
Trapping is allowed on many, but not all, conservation areas. A Special Use Permit is required, and these must be applied for at least 30 days before trapping begins. Contact the area manager at the regional office to see what opportunities are available in your area.
Federal regulations regarding trapping vary widely. Contact the managing office of the federal lands you wish to trap to find out if trapping is permitted.