Yellowstone Grand Loop + Tetons: 7-Day Figure-Eight

The Yellowstone Grand Loop is a 142-mile figure-eight that punishes anyone who rolls in without a campground confirmation: Fishing Bridge RV Park is the only full-hookup campground inside the park, and the NPS designates it for hard-sided units only because the site sits in active grizzly habitat. For the 2026 season, Bridge Bay, Canyon, Fishing Bridge, Grant Village, and Madison are booked through Xanterra at 307-344-7311 (the move to Recreation.gov begins 2027), while Indian Creek, Lewis Lake, Mammoth, Slough Creek, and Tower Fall release on Recreation.gov on a six-month rolling window. Rig length matters: Canyon caps at 40 ft, Grant Village at 50 ft, and Fishing Bridge accepts up to 95 ft with 50-amp power. This itinerary threads Jackson north through the John D. Rockefeller, Jr. Memorial Parkway, runs the Lower Loop counterclockwise, crosses Dunraven Pass (8,859 ft, opens May 22) into the Upper Loop, and exits south through the Tetons. Wolf-watch windows in Hayden Valley are dawn-tight, and the federal 100-yard rule for bears and wolves applies whether you packed a spotting scope or not.

Elevation profile, an interior plateau most visitors underestimate: Yellowstone is not a low park. Mammoth at 6,239 ft is the lowest developed area; Old Faithful sits at 7,349 ft, Canyon at 7,734 ft, Fishing Bridge at 7,792 ft, and Lake Yellowstone shoreline at 7,733 ft (NPS Yellowstone elevation survey). Dunraven Pass tops at 8,859 ft, Craig Pass on the West Thumb-to-Old Faithful run hits 8,262 ft, and Sylvan Pass on the East Entrance road peaks at 8,524 ft. Your refrigerator-on-propane sees a 10-15% drop in BTU output above 8,000 ft; manually re-light with the door open if the freezer climbs above 10 F overnight. Class C gas engines lose 18-22% horsepower at Dunraven summit — descend Mt. Washburn in low gear, not on the brakes (5,000 ft of brake fade is real and the runaway ramp at MP 27 is a one-way trip).

Rig length truth, campground by campground: Fishing Bridge RV Park is the only full-hookup option and is hard-sided only — no tent trailers, no pop-ups, no soft-walled hybrids per NPS 2026 regulation (recurring grizzly activity). Maximum length 95 ft combined unit, 50-amp service, $96/night. Bridge Bay caps at 30 ft per site (some pull-throughs to 40), no hookups, $34/night through Xanterra. Canyon caps at 40 ft, no hookups, $43/night. Grant Village handles up to 50 ft, no hookups, $42/night. Madison caps at 40 ft, no hookups, $33/night. Mammoth, Indian Creek, Lewis Lake, Slough Creek, and Tower Fall are NPS-direct via Recreation.gov six-month rolling, all 30-40 ft and below, all no-hookup, $20-25/night. Headwaters at Flagg Ranch (just south of South Entrance in Rockefeller Parkway) offers full hookups for $95-130/night and is the practical staging campground if Fishing Bridge is full.

Seasonal window, road openings drive the trip: NPS publishes road opening dates at nps.gov/yell/planyourvisit/parkroads.htm. For 2026: Mammoth-Norris-Madison-Old Faithful loop and Mammoth-Tower opened April 17, 2026 (weather delayed entry by 4 days from the announced April 13). Dunraven Pass (Tower to Canyon) and Beartooth Highway (US-212) opened May 22, 2026. East Entrance (Sylvan Pass) opened May 1. South Entrance (from Tetons) opened May 8. Grant Village campground opened June 26. Most interior roads close to wheeled vehicles November 4-7 each year; only the Mammoth-to-Cooke City road (via Lamar Valley) stays plowed year-round. Late June through mid-September is the dependable window. Hayden Valley wolf-watching peaks at first light from late May through July when wolf packs are denning.

Geothermal and wildlife rules that are not suggestions: NPS regulation 36 CFR 2.1 requires staying on boardwalks in all thermal areas — the 213 F geyser pool at Norris will kill you in seconds, and a 23-year-old fell through a thin crust at Norris in 2016 and was completely dissolved by morning (NPS incident report). The federal wildlife distance rule: 100 yards from bears and wolves, 25 yards from bison, elk, moose, and all other large mammals (36 CFR 2.2). Bison gored 9 visitors in 2024; rangers cite "selfie distance" as the root cause. Bear spray is mandatory equipment, sold at every visitor center for $50-60; airline travelers must buy after arrival.

Fuel, water, dump — interior options are limited: Diesel pumps that fit a 40 ft coach: Mammoth (Yellowstone General Stores), Tower Junction (seasonal), Canyon Village, Fishing Bridge, Grant Village, Old Faithful (Lower Hams). All Yellowstone General Stores diesel pumps are credit-card only and prices run $0.80-1.20 over Bozeman pricing. Dump stations: Bridge Bay (free for campers, $10 non-campers), Canyon (free/registered), Fishing Bridge (free/registered), Grant Village (free/registered), Madison (free/registered), Mammoth (free/registered). Potable water at every developed campground. The 51-mile West Yellowstone-to-Old Faithful run has zero services between West Yellowstone and Madison Junction; fuel before entering through the West Gate.

Cell coverage, expect 80% offline: AT&T is the only carrier with usable coverage at Old Faithful, Mammoth, Canyon, Grant Village, and Lake Village — and even there it is 1-2 bar LTE. Verizon works at Mammoth and partially at Old Faithful only. T-Mobile is dead inside the park entirely except for a faint signal at Mammoth. The 27-mile Tower-to-Canyon run over Dunraven Pass has zero coverage on any carrier. Download offline Apple/Google maps for all 1,000+ mi² before entering. Garmin inReach or Zoleo essential for SOS in the backcountry; Yellowstone SAR averages 18 days to find a lost hiker without a beacon.

Primary sources beyond what's footnoted below: nps.gov/yell (campgrounds, road status, regulations), Xanterra reservations 307-344-7311 (5-month rolling for Bridge Bay/Canyon/Fishing Bridge/Grant/Madison through end of 2026), Recreation.gov for Mammoth/Indian Creek/Lewis Lake/Slough Creek/Tower Fall, NPS Yellowstone Geyser predictions at nps.gov/yell/planyourvisit/exploringoldfaithful.htm, and Greater Yellowstone Coalition (greateryellowstone.org) for current wolf pack territories and viewing ethics.