In most commercial campgrounds, "large" is more than 30' long and 12' wide. However, in state parks, Forest Service, National Park, and Corps of Engineers campgrounds, "large" is whatever they decide it is, often less than 25' long and 8' wide. Remember than most of those Govenment campgrounds were built back in the 1930s when a 24' TT with no slide was considered "large".
So if you're staying in a KOA, then I wouldn't worry about it. But if your campground of choice is in the Chikamunga National Forest, the you need to check out the actual site you're reserving.
Grumpy ole man with over 50 years towing experience. Now my heaviest trailer is a 7,000-pound enclosed cargo trailer, RV is a 5,600 pound Skyline Nomad Joey 196S, and my tow vehicle is a 2012 F-150 EcoBoost SuperCrew.