The Dog Park at Clover Dell Park has two large, completely fenced in areas for the dogs to run off leash.  One area is for large dogs and the other for smaller breeds.  There is a shared gate, but then each has its own area so there are no chances of a dog escaping though there.  There are training aids for people getting ready to show their dog and plenty of trees for them as well.  There's even a faux fire hydrant!

There are a few rules to follow such as no spiked collars and no food (human or dog food) allowed; the rules are clearly posted.  

Check out this article from a local: Yes, Sedalia Has a Dog Park.