We stayed at Mammoth campground during our last visit to Yellowstone as we were unable to get one of the back country campsites we were hoping for. Lucky for us we arrived in the park before 10am and Mammoth had plenty of spots available. Mammoth is a first-come, first-serve campground with a well organized check-in procedures, no need to search for open campsites, the rangers at the check-in station will let you know what is available and show you on the map the available sites. Cost is$20 a night. This campground like all the ones in the park fills up fast, so get their early. The 85 site campground has paved roads with gravel parking pads. Sites have platforms for the tents. Dumpsters are though out the campground, and recycling is available at the entrance. The campground has flush toilets and water faucets are through out the grounds. Each site has its own bear proof food locker, as well as a picnic table and metal fire ring. Their is a nightly ranger program at 9:30pm. We stayed in site 77 and found the campground to be very quiet, even with the park road running right by. The slow speed of 35 mph helps keep the noise down and after about 10pm we really didn't notice cars going by. Morning traffic does start up just after 5pm, but the noise did not wake this light sleeper. Another factor that help keep noise down was the quiet hours, while this tends to do little at other campgrounds to prevent campers, and kids from being loud or from generators being run at night, the strictly enforced notice and posted$50 fine really does the job. Fire wood is available to purchase for$8 a box, kindling for$3 a bundle and they will provide matches if you need them. You do have cell service at the campground.