Which Yellowstone campgrounds are open in June, and when does the camping season typically start?

For the 2026 season, most of Yellowstone's campgrounds are already open by the start of June. Madison Campground opens earliest, on May 1, followed by Fishing Bridge RV Park on May 8, Bridge Bay on May 15, Tower Fall on May 22 and Canyon on May 29. Mammoth Campground is open year-round. That means six of the park's eleven campgrounds, Madison, Fishing Bridge RV Park, Bridge Bay, Tower Fall, Canyon and Mammoth, are running for all of June.

Three more open partway through the month: Indian Creek on June 12, and both Lewis Lake and Slough Creek on June 15. Grant Village does not open until June 26, so it is closed for nearly all of June. Pebble Creek Campground is closed outright; the park's campground page notes it was significantly impacted by the 2022 floods and will remain closed until further notice for flood recovery work. Source: https://www.nps.gov/yell/planyourvisit/campgrounds.htm

So by early June a visitor has Madison, Fishing Bridge RV Park, Bridge Bay, Tower Fall, Canyon and Mammoth to choose from. By mid-June, Indian Creek, Lewis Lake and Slough Creek join that list. Grant Village and Pebble Creek remain the exceptions through most or all of the month.

In terms of when the season typically starts, Madison's May 1 opening marks the earliest start among the park's frontcountry campgrounds, with the rest phasing in through May and June as snow clears and lake levels drop. Reservations for all reservable campgrounds open on a rolling basis exactly six months before the date of the stay. Mammoth is the only campground with first-come, first-served camping, available from October 15 through April 1, after which it also requires a reservation.

These are the published 2026 dates and the park states that all dates are subject to change, so it is worth checking the park's current conditions page before a trip. Source: https://www.nps.gov/yell/planyourvisit/campgrounds.htm