We do offer reservation requests for many of the private campgrounds listed on The Dyrt. Simply submit your request and the campground manager has 24 hours to accept or decline your request, depending on site availability. More private campgrounds are enabling booking requests each week.
For private campgrounds that have not yet enabled booking requests on The Dyrt, you can always call the campground directly or visit their own website to check on availability.
Note, National and State Parks mostly use recreation.gov or reserveamerica.com for reservations.