Whether you are going on your first camping trip or your fiftieth, these websites well help you find the best campsite.
This is my personal favorite. Recreation.gov houses all of the reservable federal (Forest Service, BLM, National Park Service) campgrounds, minus a few extra special National Park ones. You can search by area or map, cruise different dates to see when sites are open, read reviews, and pick out the perfect spot based on campground maps. Some wilderness permits are also available here, making it a good one stop shop.
Very similar to recreation.gov, Reserve American includes most federal campgrounds, state campgrounds, as well as some privately managed sites. The user interface is very similar to recreation.gov in the way you search and reserve sites. Generally, I like to check both of these sites and compare what I find.
When in doubt, Google it out. The best way to find campgrounds in Google is to find the area you are looking to camp on Google Maps, search “campground” in that area, and start checking out what you find. This tactic will usually turn up more privately managed campgrounds though, so be weary. Generally these cost more and have nearly enough amenities to be a hotel.
If you are down with dispersed camping, make sure you check out freecampsites.net. This user created website catalogs free campsites all over the place, gives detailed directions on how to get there, and sometimes offers photos. These of course do not come with a guarantee that the site won’t be taken when you get there, will have no amenities, and you will need to follow Leave No Trace practices while out dispersed camping.
Forest Service, BLM, and National Park websites
There are quite a few campgrounds that can only be found on these websites, usually because they are non reservable and so, not as popular on the internet. Nevertheless, they exist and are usually much cheaper and quieter than the reservable ones. You will just need to search by the BLM district, National Forest/Grassland, or National Park you are looking to camp in.