Flat Rock (Idaho)

Show on map208-558-7658 OR 208-270-0094
HIGHWAY 20
ISLAND PARK, ID 83429

Overview

Flat Rock Campground is located 22 miles south of West Yellowstone, Montana and 30 miles north of Ashton, Idaho in beautiful Island Park, Idaho. Flat Rock is adjacent to U.S. Highway 20 and the Henry's Fork of the Snake River at an elevation of 6,400 feet.

Recreation

Henry's Fork has great fly-fishing for rainbow and brook trout. The river's headwaters are at Big Springs, one of the nation's largest springs, just 4.5 miles from the campground. Tubing, canoeing, kayaking and rafting are also popular on the river.

The Big Springs National Recreation Water Trail begins at Big Springs and ends just northeast of the campground at Macks Inn. It offers a lazy three-hour float or canoe trip through beautiful scenery. Wildlife, including moose, bald eagles and Sandhill cranes, is often seen along the trail.

Hiking, biking, horseback riding and ATVing are popular activities. Many miles of trails crisscross Island Park, including the 2.5-mile Coffee Pot Rapids Trail, which begins at nearby Upper Coffee Pot Campground and meanders along the riverbank. The Continental Divide National Scenic Trail and the Nez Perce Trail are in the area.

Island Park Reservoir and Henry's Lake are nearby, both offer boating, water skiing and excellent fishing opportunities.

Facilities

The campground contains single and double campsites, some of which have 50-amp electric hookups. Sites are equipped with picnic and utility tables, a campfire ring and tent pad.

Vault toilets, drinking water and trash collection are provided. All interior roads and parking spurs are gravel.

Macks Inn is just across the highway from the campground and offers amenities such as boat rentals, shuttle service, showers, laundry facilities, gas and groceries.

Natural Features

Island Park is composed of two areas of extinct volcanic activity. The Henry's Fork Caldera sits inside the larger Island Park Caldera. The area is known for its dense forests of lodgepole pine, broad grassy meadows bursting with summer wildflowers and a wide variety of wildlife, including black and grizzly bears, moose, elk, deer, bald eagles, Sandhill cranes and much, much more.

A mixed growth of lodgepole pine forest provides partial shade. A portion of one loop is fairly close to the river and some sites have river views.

Nearby Attractions

Mesa Falls Scenic Byway is 11 miles south of the campground. This 28-mile road leads to scenic overlooks and trails at 110 foot Upper Mesa Falls and 85 foot Lower Mesa Falls.

Harriman State Park is 13 miles south. The Henry's Fork meanders through the Harriman, offering excellent fishing. Over 20 miles of trails are available, and wildlife is abundant in this scenic park.

Henry's Lake State Park is 10 miles north, offering fishing, a fish cleaning station and boat ramp.

Yellowstone National Park's west entrance is just 22 miles north in the town of West Yellowstone, Montana. Visitors enjoy day-tripping to the park for unparalleled wildlife viewing and the beautiful and unique scenery.

Camp site features

Across 16 camp sites:

  • Electric hookups: 6 of 16 sites
  • Fire pit: all 16 sites
  • Picnic table: all 16 sites
  • Longest RV: 65 ft
  • Largest party: 16 people
  • Power up to 50 amps
  • Equipment: RV, Tent, Trailer

Directions

From West Yellowstone, Montana, take U.S. Highway 20 south for 22 miles, or from Ashton, Idaho, take U.S. Highway 20 north for 30 miles. The campground entrance is 1/4 mile south of Macks Inn on the west side of the highway.

Stay Limit

Check in from 2 PM, check out by 12 PM.

Reviews

108 reviews
5 stars
59
4 stars
27
3 stars
11
2 stars
4
1 stars
7
Mary V
Loop:Flat
Site:
Reviewed 2 months ago
Audi has no consistently. This place had no communication, no way to figure out that not only services closed but the actual gates closed within 20 hours of a date you took e\reservtion. Host w\said she “had a life too” and that is why campground gates were closing on just sept. 15. Buffalo campground had completely different maintenance and host vibe. We left and did not even stay even though we paid. I definitely would not want Audi if this is the mode of peration. Can’t call anyone to even ask a question.
Matt H
Loop:Flat
Site:
Reviewed 2 months ago
Anne/Annie(?) was extremely helpful and friendly. She made sure we behaved safely by checking whether we had proper bear deterrents, and were storing our food and supplies in a way to keep everyone, and all the wildlife safe. She informed us of the recent lift of the burn ban and supplied us with a small amount of firewood for our last night there. We even had vehicle issue, and she was willing to help us jump-start our dead battery. The whole site was very clean, no trash laying around, and the bathrooms were very clean, and almost completely odor free (for an open pit toilet, that's rare). The sites were spacious, flat, and well laid out. All in all, a very nice stay!
Jeffrey S
Loop:Flat
Site:
Reviewed 2 months ago
The campground and bathroom facilities were very well maintained. You could hear traffic though as it was located near the main road. The camping spot had enough room to put tents on fairly easily. It was quiet. The only issue was the light from the bathroom was glaring right into our camping spot. It didn't keep us awake or anything so it wasn't terrible, but it was nice to have a bathroom nearby too. The lady that came to collect for a third car was rude at first with my wife, but I also thought maybe by the end of the camping season, she'd seen her share and expected pushback. Once we paid, she was good with us and drove off. But overall was a good experience. Don't know if I'll come back as it was close to the main road, the light and keeper. But even then maybe a different spot would've been better. It was our first time there so you don't know what you don't know.
Grant H
Loop:Flat
Site:
Reviewed 2 months ago
Helpful host
Tom R
Loop:Flat
Site:
Reviewed 2 months ago
Great place to spend a few days at.
Andrew M
Loop:Flat
Site:
Reviewed 2 months ago
It would have been nice if the campsite information provided the distance to the river for each campsite. I wanted to fly fish and was pretty far away from the water and I could have had a sight right next to the water. But your information online doesn't give you that
Availability

See the Camp Sites section below to find detailed booking availability.

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Season dates

Peak season

May 22, 2027 – Sep 15, 2027

Reservable online

Peak season

May 22, 2028 – Sep 15, 2028

Reservable online

Camp Sites

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