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Tent Sites
Fires Unknown
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Drinking Water
About Flat Rock (Idaho)

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.


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.


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.

ADA Access: N

$20.00 - $52.00
National Forest
Drive In
Boat In
ADA Accessible
Alcohol Allowed
Drinking Water
Firewood Available
Pets Allowed
Phone Service
Picnic Table
Sanitary Dump
Trash Available
Flat Rock (Idaho) is located in Idaho
44.4969 N
-111.34 W
Get 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.
4 Reviews of Flat Rock (Idaho)
Beautiful view

Easy access of highway 20

One of my favorites! Take it from a religious camper

This is a busy campground. It is perfect for floating, fly fishing, and ATV riders. I even got some good mountain biking in. There is a canoe/float rental right next door. Despite all the activity - the sites feel more secluded than most camp grounds and are nothing less than relaxing! No showers but there are bear boxes every couple of spots and running water. Pit toliets and we paid $15/night. Only planned on staying one night - ended up staying two!

Nice spot

Just spend your time exploring. You'll be happy wherever you go.

First to Review
Awesome campsite

This site was so empty. This site was really great and you had your own privacy. The site came with electric hookups, tables and a fire ring. the restroom is very clean and has a shower. We stayed at site 8 and the table and rings looked pretty new. It seemed like the site is not used often. Firewood is very hard to find out here and I recommend bringing your own supply. At night the temperature drops dramatically and i recommend bringing a down jacket or just extra layers. Near the campsite is a river and there is people from other camps fly fishing for trout. The river is your only source of water and you should boil it because there my be giardia. In the morning I recommend going to Mesa falls which is about a 20 minute drive from the site and it is so beautiful.