US lakes & pondsUS lakes & pondsRV park · National forest in Island Park, Fremont County, Idaho.
| Managed by | USDA Forest Service (Caribou-Targhee National Forest) |
|---|---|
| Campsites | 16 |
| Site types | 10 standard, no electric, 6 standard, electric |
| RV hookups | Electric hookups at 6 sites |
| Longest RV/trailer site | 65 ft |
| RVs welcome | Yes |
| Tent sites | Yes |
| Phone | (208) 558-7658 |
| Reservations | Recreation.gov |
We only list amenities a source records. A missing item doesn't mean the campground lacks it, so check with Mack's Inn RV park before you go.
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.
Description: Recreation.gov (U.S. federal government, public domain), shortened.
Lakes and ponds on LakeRipple within 10 miles, closest first (straight-line distance to the shoreline). Each page has boat launches, beaches, fishing and today's weather.
Mack's Inn RV park is in Island Park, Fremont County.
Sources: Recreation.gov (RIDB) · OpenStreetMap contributors (ODbL). Pulled Oct 12, 2026. Interactive map: Leaflet with © OpenStreetMap contributors. Seasons, rates and rules change; confirm with the campground.