Yellowstone (Wyoming) · Wyoming
Mammoth Campground is the only year-round campground in Yellowstone National Park, a sagebrush-and-juniper hillside loop just below Mammoth Hot Springs near the North Entrance in Wyoming, five miles from Gardiner, Montana. It is the lowest and mildest campground in the park, which is why our full review sends early-season, late-season, and winter RVers here. Elk wander the loops daily, and it is the closest in-park camping to Lamar Valley and the northern range.
| Hookups | None (dry). Dump station seasonally; flush toilets. |
|---|---|
| Sites | Around 85. |
| Max RV length | Up to about 40 feet, though larger combined-length sites exist; most sites favor mid-size rigs. |
| Cost | Around $25–$30/night. |
| Reservations | Recreation.gov (or walk-up in the off-season window). |
| Season | Open year-round; first-come, first-served only from October 15 to April 1, reservations the rest of the year. |
| Best for | Off-season and shoulder-season camping, North Entrance arrivals, mid-size rigs. |
Mammoth Campground is the only year-round campground in Yellowstone National Park, a sagebrush-and-juniper hillside loop just below Mammoth Hot Springs near the North Entrance in Wyoming, five miles from Gardiner, Montana. It is the lowest and mildest campground in the park, which is why our full review sends early-season, late-season, and winter RVers here. Elk wander the loops daily, and it is the closest in-park camping to Lamar Valley and the northern range.
It is dry camping: no hookups, but flush toilets, potable water, and a seasonal dump station, with generators allowed in posted daytime hours. Around 82 to 85 sites run roughly $25 a night. Rig limits are combined length: about 40 to 45 feet in the summer season per the NPS table, dropping to 30 feet in winter, and the sloped loop favors mid-size rigs. Book on Recreation.gov six months out for April through mid-October; from October 15 to April 1 it is first-come, first-served, the only walk-up camping in the park. The trade-off is location: Old Faithful and the lake are 50-plus miles away.
Excerpts from the RV Parks Guide articles that cover this campground. Each links to the full guide.
Full review
Mammoth Campground Review: Yellowstone's Only Year-Round CampgroundMammoth Campground in Yellowstone: 82 dry sites at $25 a night, 45-foot summer and 30-foot winter limits, Recreation.gov in season and first-come Oct 15–Apr 1. What it's like and who it fits.
Regional guide
RV Camping in Yellowstone National Park: Every In-Park Campground for 2026In the northwest near the North Entrance, the only year-round campground in Yellowstone. Lower elevation, sagebrush and juniper terrain, and a reliable spot for elk in town.
Read the guide →Our verdict
Book Mammoth for shoulder-season and winter trips, Lamar Valley wildlife, and the days nothing else is available. Skip it if you need hookups, showers, or a central base for the whole park.
No. It is dry camping with flush toilets, potable water, and a dump station in season. Generators are allowed during posted daytime hours.
About $25 per night per the NPS 2026 table; our Yellowstone guide lists a $25 to $30 range. Confirm at booking.
Roughly 40 to 45 feet combined in the summer season and 30 feet combined from mid-October through April. Enter your true combined length on Recreation.gov, since not every site fits the maximum.
Yes, it is the only Yellowstone campground that stays open all year. Expect reduced services in winter.
From April through mid-October, book on Recreation.gov six months out. From October 15 through April 1 it is first-come, first-served.
Gardiner is five miles north through the North Entrance. Lamar Valley is about an hour's drive east via Tower Junction.
Compare alternatives before you book — or browse the whole Wyoming hub.