One thing I'm quickly learning during this first year on the road is how ridiculously busy our national parks have become. Right now I'm in Yellowstone National Park in August and it's just astounding how many people are entering the park each day.
Yellowstone campground reservations can fill up more than 6 months in advance, so a last minute visit can feel kind of intimidating. On the plus side, there are seven first-come, first-serve campgrounds available in the park and open sites are given away each morning starting with the first person in line. The catch - you have to show up really early to snag a spot!
My morning started here - 6:30 am, first in line at the Mammoth Campground registration office near the north entrance of Yellowstone National Park.
At 7:00 am two rangers showed up to start checking in new campers. I got the first site available and was parked and set up before 8:00 am. By 9:45 am the campground office was closed again and marked full for the day. There is a handy page from the Yellowstone National Park website that shows the campground fill times for the current and previous day. I kept an eye on this page for a few days before driving into the park to get an idea of how early I should arrive to get a spot.
Almost all of the sites at Mammoth are large pull-through sites with more than enough space for any size rig. This is my site, #26 on the outside of the lower loop. I paid $20 per night for four nights of dry camping.
I have a really nice view looking down and across the valley from the front of my site.
In the afternoon I took a walk across the road and up one of the hills next to the campground. There was a really nice view from up there looking down the valley towards the north entrance and to the left over Mammoth campground and Mammoth Hot Springs above the campground in the distance.
From here you can easily see the layout of the campground. It's one big u-shaped loop with pull-through sites on the inside and outside of the loop. The big negative of Mammoth is that it sits inside a huge bend in the main park road. There is a lot of road noise because of this especially during busy times of day. If given a choice I would ask for one of the upper sites near the back of the loop like 50-53 just to give yourself more space between you and the main road and cut down some of the noise.