Assuming you are talking about NF campgrounds, unfortunately, there is no easy way. You might get partial results from various publications, e.g. Trailer Life Directory. The reservation system (www.recreation.gov
) will have more than most but there are campgrounds with full hookups that aren't reserveable and not listed in the Directory. And, they don't have a search capability where you can list just full hookup campgrounds in or across NFs.
W/O tooting our horn, the U.S. NF Campground Guides (click icon upper left) are probably the only publications that lists all of them, give or take one or two. Problem is searching our website (using the Google search engine, for example) is incomplete and we don't have a search engine. However, unavailable to the public, we do have databases where such searches can be done. Tell me which state(s) you are talking about and I'll pull the data - sorted by state, forest name and campground name. You can then go to our website to get the campground details . . . Fred