Oklahoma City
Tulsa, OK
Shawnee, OK
Columbia, MO
Wayne County, MI
Claremore, OK
That's just personal experience. In general, I would expect a camping or RV parking area with some kind of hookups at most fairgrounds or expo centers that hold extended agricultural events. Farmers have been hauling trailers to live in to state and county fairs for about 80 years, long before there was an industry to coin the term RV. Before that, horse drawn house wagons, sometimes called caravans.
Not strictly fairgrounds, but cities will have RV parks meant to support events like rodeo and to provide for seasonal worker (so they don't end up parking in the street). Two I've visited in Kansas are Coffeyville and Chanute. Wichita Falls in Texas has a park specifically for transients at the end of I-44.