Openings · last 7 days
272
Booking reality
Campsite Sniper detected 272 site openings here in the last 7 days
01 · Detected Opening History · the openings record · file CS-247571
When Mammoth Campground (Yellowstone) reopens
Mammoth Campground (Yellowstone)'s openings record: every site-date Campsite Sniper detected turning available, logged and time-stamped. Refreshed hourly.
Openings · last 30 days
279
Openings · last 90 days
279
Weekday pattern
Detected openings by day of week · 90dThursday accounted for the largest share of the openings Campsite Sniper detected. 72 of 279 openings detected in the last 90 days occurred on a Thursday (25.8%), with Friday (46) and Sunday (41) next in line.
Hour-of-day pattern
First detected by hour · local time · last 90 daysThe largest concentrations of detected openings were first detected during the 06:00 and 08:00 local-time hours. Those hours contained 144 of 279 detected openings (51.6%). Hours show when Campsite Sniper first detected each opening, in Mountain Time, not when the change was made upstream.
Lead-time profile
Days before stay date · percentilesHalf of the openings Campsite Sniper detected appeared at least 14 days before the stay date; the middle 50% land 4.5–14 days out. Set an alert if you want Campsite Sniper to monitor future openings.
Highest-churn sites
Most openings · 90d| Site | Openings | Share of all openings |
|---|---|---|
| Mammoth site #13 | 11 | 3.9% |
| Mammoth site #32 | 11 | 3.9% |
| Mammoth site #34 | 11 | 3.9% |
| Mammoth site #4 | 10 | 3.6% |
| Mammoth site #28 | 10 | 3.6% |
Site Mammoth site #13 had the most detected openings in the last 90 days: 11. One free watch covers every site here.
02 · Availability Outlook · Sep 18, 2026 – Mar 19, 2027 · of 81 monitored sites
Of the 14,823 tracked site-nights (Sep 18, 2026 – Mar 19, 2027): 563 open for online reservation · 1,705 reserved · 5,890 on sites not offered for online reservation (first-come, first-served or administrative) · 6,665 closed.
Where the open windows are
96.2% of tracked site-nights are not currently open for online reservation. 563 of 14,823 remain open; here is where they are.
Load status
Sep 18, 2026 – Mar 19, 2027Not open online96.2%
Open site-nights563 / 14,823
Reserved (of online inventory)1,705 / 2,268
Weekday openings365
Weekend openings198
Of the open site-nights on mapped sites, 365 fall on weekdays and 198 on weekends (Fri–Sun).
Open dates by month
Sep 2026 – Mar 2027November shows no online availability. 0 of 2,430 tracked site-nights are open there — 1,140 on sites not offered online, 1,290 closed.
Holiday windows
Sites open per night · of 81 sites| Window | Night | Sites open | Status |
|---|---|---|---|
| Labor Day | SAT Sep 5 | 0 | None open |
| SUN Sep 6 | 0 | None open | |
| MON Sep 7 | 0 | None open | |
| Thanksgiving | THU Nov 26 | 0 | None open |
| FRI Nov 27 | 0 | None open | |
| SAT Nov 28 | 0 | None open | |
| Christmas | THU Dec 24 | 0 | None open |
| FRI Dec 25 | 0 | None open | |
| New Year | THU Dec 31 | 0 | None open |
| FRI Jan 1 | 0 | None open |
Labor Day: no online availability on any tracked night. Thanksgiving: no online availability on any tracked night. Christmas: no online availability on any tracked night. New Year: no online availability on any tracked night.
Best-availability sites
Most open site-nights · tracked window| Site | Open site-nights |
|---|---|
| Mammoth site #15 | 15 |
| Mammoth site #2 | 14 |
| Mammoth site #21 | 14 |
| Mammoth site #24 | 14 |
| Mammoth site #36 | 14 |
The 5 sites with the most open site-nights in the current snapshot. Pair a bookable date with a free alert to cover everything else.
Next windows
As of Sep 18, 2026 snapshotNext open dateSat · Sep 19
Next open weekendSat · Sep 19
November0 of 2,430 · no online availability
The next bookable night is Sep 19; the first open weekend starts Sep 19. Campsite Sniper can watch later dates for you.
Stays and site detail
563 open site-nights across 58 sites at Mammoth Campground (Yellowstone), from the same hourly snapshot as everything above.
Multi-night stays. 50 2-night, 45 3-night, 43 7-night openings where a single site is free for every night, per Campsite Sniper's current snapshot — soonest Oct 2 at site Mammoth site #15.
RV length. Longest recorded site here is 99 ft. 78 sites take 25 ft, 72 sites take 35 ft, 70 sites take 40 ft.
All 58 sites with current availability
| Site | Max RV | Hookups | Open site-nights | Longest run | Dates |
|---|---|---|---|---|---|
| Mammoth site #15 | 40 ft | None | 15 | 14 nights | Sep 30, Oct 2, Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12 +3 more |
| Mammoth site #2 | 50 ft | None | 14 | 13 nights | Sep 23, Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13 +2 more |
| Mammoth site #21 | 52 ft | None | 14 | 14 nights | Oct 2, Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13 +2 more |
| Mammoth site #24 | 60 ft | None | 14 | 14 nights | Oct 2, Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13 +2 more |
| Mammoth site #36 | 46 ft | None | 14 | 14 nights | Oct 2, Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13 +2 more |
| Mammoth site #11 | 55 ft | None | 13 | 13 nights | Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14 +1 more |
| Mammoth site #12 | 53 ft | None | 13 | 13 nights | Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14 +1 more |
| Mammoth site #13 | 50 ft | None | 13 | 13 nights | Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14 +1 more |
| Mammoth site #14 | 66 ft | None | 13 | 13 nights | Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14 +1 more |
| Mammoth site #17 | 37 ft | None | 13 | 13 nights | Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14 +1 more |
| Mammoth site #18 | 60 ft | None | 13 | 13 nights | Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14 +1 more |
| Mammoth site #29 | 40 ft | None | 13 | 13 nights | Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14 +1 more |
| Mammoth site #3 | 52 ft | None | 13 | 13 nights | Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14 +1 more |
| Mammoth site #30 | 99 ft | None | 13 | 13 nights | Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14 +1 more |
| Mammoth site #35 | 33 ft | None | 13 | 13 nights | Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14 +1 more |
| Mammoth site #38 | 56 ft | None | 13 | 13 nights | Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14 +1 more |
| Mammoth site #40 | 57 ft | None | 13 | 13 nights | Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14 +1 more |
| Mammoth site #42 | 62 ft | None | 13 | 13 nights | Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14 +1 more |
| Mammoth site #61 | 51 ft | None | 13 | 13 nights | Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14 +1 more |
| Mammoth site #67 | 77 ft | None | 13 | 13 nights | Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14 +1 more |
| Mammoth site #7 | 60 ft | None | 13 | 13 nights | Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14 +1 more |
| Mammoth site #73 | 49 ft | None | 13 | 13 nights | Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14 +1 more |
| Mammoth site #8 | 62 ft | None | 13 | 13 nights | Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14 +1 more |
| Mammoth site #9 | 62 ft | None | 13 | 13 nights | Oct 3, Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14 +1 more |
| Mammoth site #16 | 53 ft | None | 12 | 12 nights | Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14, Oct 15 |
| Mammoth site #19 | 56 ft | None | 12 | 12 nights | Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14, Oct 15 |
| Mammoth site #22 | 80 ft | None | 12 | 12 nights | Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14, Oct 15 |
| Mammoth site #25 | 58 ft | None | 12 | 12 nights | Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14, Oct 15 |
| Mammoth site #28 | 26 ft | None | 12 | 12 nights | Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14, Oct 15 |
| Mammoth site #32 | 58 ft | None | 12 | 12 nights | Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14, Oct 15 |
| Mammoth site #33 | 61 ft | None | 12 | 12 nights | Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14, Oct 15 |
| Mammoth site #34 | 25 ft | None | 12 | 12 nights | Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14, Oct 15 |
| Mammoth site #6 | 60 ft | None | 12 | 12 nights | Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14, Oct 15 |
| Mammoth site #72 | 52 ft | None | 12 | 12 nights | Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14, Oct 15 |
| Mammoth site #84 | 48 ft | None | 12 | 12 nights | Oct 4, Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14, Oct 15 |
| Mammoth site #26 | 58 ft | None | 11 | 11 nights | Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14, Oct 15 |
| Mammoth site #5 | 68 ft | None | 11 | 11 nights | Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14, Oct 15 |
| Mammoth site #63 | 64 ft | None | 11 | 11 nights | Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14, Oct 15 |
| Mammoth site #70 | 38 ft | None | 11 | 11 nights | Oct 5, Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14, Oct 15 |
| Mammoth site #20 | 56 ft | None | 10 | 10 nights | Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14, Oct 15 |
| Mammoth site #23 | 96 ft | None | 10 | 10 nights | Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14, Oct 15 |
| Mammoth site #27 | 58 ft | None | 10 | 10 nights | Oct 6, Oct 7, Oct 8, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14, Oct 15 |
| Mammoth site #4 | 52 ft | None | 8 | 7 nights | Sep 30, Oct 9, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14, Oct 15 |
| Mammoth site #39 | 54 ft | None | 7 | 6 nights | Sep 19, Oct 10, Oct 11, Oct 12, Oct 13, Oct 14, Oct 15 |
| Mammoth site #10 | 66 ft | None | 5 | 5 nights | Oct 11, Oct 12, Oct 13, Oct 14, Oct 15 |
| Mammoth site #48 | 56 ft | None | 2 | 2 nights | Oct 4, Oct 5 |
| Mammoth site #71 | 48 ft | None | 2 | 2 nights | Oct 14, Oct 15 |
| Mammoth site #76 | 42 ft | None | 2 | 2 nights | Oct 14, Oct 15 |
| Mammoth site #80 | 30 ft | None | 2 | 2 nights | Oct 14, Oct 15 |
| Mammoth site #81 | 50 ft | None | 2 | 1 night | Sep 30, Oct 14 |
| Mammoth site #85 | 46 ft | None | 2 | 2 nights | Oct 14, Oct 15 |
| Mammoth site #31 | 48 ft | None | 1 | 1 night | Oct 15 |
| Mammoth site #52 | 55 ft | None | 1 | 1 night | Sep 23 |
| Mammoth site #55 | 33 ft | None | 1 | 1 night | Oct 10 |
| Mammoth site #69 | 33 ft | None | 1 | 1 night | Sep 22 |
| Mammoth site #77 | 22 ft | None | 1 | 1 night | Oct 15 |
| Mammoth site #79 | 24 ft | None | 1 | 1 night | Oct 15 |
| Mammoth site #83 | 50 ft | None | 1 | 1 night | Oct 15 |
About Mammoth Campground (Yellowstone)
Overview
Starting Tuesday April 15th, the Mammoth Campground is open and reservations are required.
For reservations at the campgrounds managed by Yellowstone National Park Lodges (Fishing Bridge RV Park, Bridge Bay, Canyon, Madison, and Grant Village campgrounds), please visit the Yellowstone National Park Lodges Camping website.
Recreation
There are many recreational opportunities in the Mammoth Hot Springs and the North area. Visit these pages to learn more:
Boating
Fishing
Hiking
Photography & Wildlife Watching
Explore the boardwalks above Mammoth Hot Springs to view the the steaming Hydrothermal Features or take a drive around the vibrant travertine terraces.
Explore in Winter. Ski or snowshoe among the whiffs of sulfur along the Upper Terraces.
Explore the historic Fort Yellowstone area.
Visit the park's Mammoth & Hot Springs North web page to learn more.
Facilities
Mammoth Campground offers:
82 campsites Some Cell Phone Reception Food Storage Lockers Trash/Recycling Collection Amphitheater - Seasonal Staff or Volunteer Host On Site - Seasonal Potable Water spigots Flush Toilets - year round
There are no showers at the campground
Natural Features
The Mammoth Campground is in a high sagebrush steppe, scattered juniper and Douglas fir trees provide shade during hot summer months. Wildlife including elk, bison, pronghorn, and mule deer frequent the Mammoth Hot Springs and the North area of the park, depending on the season.
The road from the North Entrance to the Mammoth Campground winds up the Gardner River canyon, past crumbling walls of sandstone and ancient mudflows. The vegetation is much thicker in the canyon than on the open prairie down below, the common trees being Rocky Mountain juniper, cottonwood, and Douglas-fir. Low-growing willows also crowd the river's edge in the flatter, flood-prone sections of the canyon. Watch for wildlife, which varies by the season. Eagles, osprey, dippers, and kingfishers can be spotted along the river, while bighorn sheep climb along the steeper parts of the canyon. Elk are common in Mammoth Hot Springs, while bison can often been seen along the road out to Tower–Roosevelt.
Spring and Fall daytime temperatures range from 30°F (-1°C) to 60°F (15°C) with overnight lows in the teens to single digits. Snow is common in the spring and fall. Summer temperatures are often around 70°F (21°) to 80°F (27°C) and occasionally 90°F (32°F) at lower elevations. Nights are usually cool and temperatures may drop below freezing at higher elevations. Thunderstorms are common in the afternoons. During winter, sub-zero temperatures and snow are common, especially at night and at higher elevations. Winter temperatures range from 0—20°F (-20—-5°C) throughout the day, with sub-zero temperatures overnight.
81 monitored sitesRVs up to 99 ftNo hookups5 shadedPets OKFire pitsMax party 6
Getting there
The Mammoth Campground is located in the Mammoth Hot Springs area in the Northen section of the park, five miles from the park's North Entrance near Gardiner, MT. Visit the park's website for more information including directions and maps: https://www.nps.gov/yell/planyourvisit/directions.htm
Yellowstone National Park, Yellowstone, WY 82190307-344-2107
AmphitheaterAuto TouringBirdingCampingCross Country SkiingCultural ActivitiesFishingHikingHistoric & Cultural SiteInterpretive ProgramsSkiingVisitor CenterWildlife Viewing
View on Recreation.gov ↗ Get directions ↗
03 · Field Photos · roll CS-247571 · facility
Photo gallery
Roll CS-247571 · Mammoth Campground (Yellowstone) · Yellowstone WY12 frames · facility
FAQ
How do I get a reservation at Mammoth Campground (Yellowstone)?
Reservations for Mammoth Campground (Yellowstone) are made through Recreation.gov. 96.2% of tracked site-nights are not currently open for online reservation; 563 of 14,823 remain open. Campsite Sniper has also detected 279 site openings here in the last 90 days, so further dates may appear. Pick a site on the map to see its calendar, or set a free Campsite Sniper alert. You complete the reservation yourself on Recreation.gov.
Does Campsite Sniper book this campground for me?
No. Campsite Sniper sends alerts and direct Recreation.gov links. It never books, pays for, holds, hoards, or resells reservations.
How current is this availability data?
Campsite Sniper re-checks public Recreation.gov availability for this facility every hour and republishes whenever anything changes. This facility's data last changed at Sep 18, 2026 16:19 UTC; an older timestamp means nothing has changed since that time, not that checking stopped. Always confirm final availability on Recreation.gov when you book.
How often do new openings appear at Mammoth Campground (Yellowstone)?
Campsite Sniper detected 272 site-date openings at Mammoth Campground (Yellowstone) in the last 7 days, 279 over 30 days and 279 over the last 90.
Which day of the week had the most detected openings at Mammoth Campground (Yellowstone)?
Thursday accounted for the largest share of the openings Campsite Sniper detected in the last 90 days: 72 of 279 (25.8%). Days reflect when Campsite Sniper first detected each opening, not when the change occurred upstream.
Can I get a multi-night stay at Mammoth Campground (Yellowstone)?
45 three-night openings are showing, counting only runs where the SAME site is free for all three nights. The soonest starts Oct 2 at site Mammoth site #15. Confirm and book on Recreation.gov.
Which sites at Mammoth Campground (Yellowstone) fit a 35-foot RV?
72 of the 81 sites that support RV analysis have a recorded maximum of 35 ft or more; the longest recorded is 99 ft.
Which month has the most availability at Mammoth Campground (Yellowstone)?
October 2026, with 556 open site-nights in the current snapshot of 2,511.
How far ahead of a stay do openings appear at Mammoth Campground (Yellowstone)?
Half of the openings Campsite Sniper detected appeared at least 14 days before the stay date; the middle 50% landed 4.5-14 days out. Campsite Sniper can monitor future changes for dates you select.
When is the next open date at Mammoth Campground (Yellowstone)?
As of the Sep 18, 2026 snapshot: the next open date is Sat, Sep 19 and the next open weekend starts Sat, Sep 19. Detected openings can add earlier dates at any time; a free Campsite Sniper alert catches those the moment they appear.
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