Tongue River Reservoir State Park is a public state park in Montana near Decker in Big Horn County. Spanning 642 acres and established in 1983, this park offers a peaceful retreat into nature for visitors of all ages.
Quick Facts
| State | Montana |
| Nearest City | Decker |
| County | Big Horn |
| Park Size | 642 acres |
| Established | 1983 |
| Google Rating | ⭐ 4.5/5 (400 reviews) |
Location & Getting There
Tongue River Reservoir State Park is located near Decker, Montana. The park’s coordinates are 45.0997, -106.7944.
Things to Do
Montana state parks offer access to the raw, untamed beauty of the “Big Sky” state, featuring alpine glacial lakes, immense river canyons, Old West ghost towns, and Native American buffalo jumps. Activities are deeply rooted in the wilderness experience: world-renowned fly fishing on blue-ribbon trout streams, hiking and mountain biking in bear country, floating and kayaking crystal-clear rivers, and camping in remote, scenic locations. The parks also serve as unparalleled gateways for wildlife viewing, including eagles, bighorn sheep, and elk.
Best Time to Visit
Summer (late June to August) is the primary window for visiting Montana parks, offering warm days, accessible high-elevation trails, and peak water recreation. Fall (September–October) is stunning with golden aspens and excellent, uncrowded fishing, though snow can arrive early. Winter is long and harsh, closing many park roads, but select parks offer ice fishing and cross-country skiing. Spring is beautiful but often hampered by muddy trails and high, murky river runoffs until late June.
Visitor Tips
Montana residents who pay the state parks fee with their annual vehicle registration enter for free. Out-of-state visitors pay a day-use fee (typically $8 per vehicle). Bear safety is critical: carry bear spray, know how to use it, hike in groups, make noise, and strictly adhere to food storage regulations when camping. Many parks have limited amenities (pit toilets, no running water), so prepare for a more rustic experience. Weather can change drastically—snow is possible in the mountains even in July.
Frequently Asked Questions
Do Montana state parks require an entrance fee?
Montana residents can enter free if they pay the state parks fee with their vehicle registration. Non-residents pay a day-use fee of approximately $8 per vehicle. No annual pass is available for non-residents.
Do I need bear spray at Montana state parks?
Bear spray is strongly recommended at most Montana state parks, especially in the western and mountainous regions. Black bears and grizzly bears are present. Carry spray, know how to use it, and follow food storage rules.
What are the best state parks near Glacier National Park?
Whitefish Lake, Wayfarers (on Flathead Lake), and Lone Pine are accessible parks near Glacier. Flathead Lake is the largest natural freshwater lake west of the Mississippi and offers excellent camping.
Can it snow in Montana state parks in summer?
Yes, snow is possible in Montana mountain parks even in July and August at higher elevations. Weather can change dramatically and quickly. Always carry layers, rain gear, and be prepared for cold conditions.
Explore More Montana State Parks
Tongue River Reservoir State Park is one of many outstanding state parks in Montana. Discover more parks in our Best State Parks in Montana guide, or use our Park Finder to search by activity, location, or features.
More parks nearby: Rosebud Battlefield State Park is a short drive away, while Chief Plenty Coups State Park lies elsewhere in the state.
Camping reservations: Book campsites and cabins for Montana state parks online at montanastateparks.reserveamerica.com.
🐾 Dogs & Pets at Tongue River Reservoir State Park
- Pets allowed? statewide rule
- Pets are allowed at most Montana state parks but must be leashed and not left unattended.
- Leash rule statewide rule
- Leash no longer than 8 feet required, unless otherwise posted.
- Beaches & swim areas statewide rule
- Pets are prohibited from swimming beaches and posted restricted areas.
- Statewide exceptions statewide rule
- Pets prohibited at Frenchtown Pond and Wild Horse Island; kennel service offered during Lewis and Clark Caverns tours; Spring Meadow Lake no pets April 16 - October 14; Lake Elmo has a fenced dog park.
Are dogs allowed at Tongue River Reservoir State Park?
Pets are allowed at most Montana state parks but must be leashed and not left unattended. Individual parks can post stricter rules — check signage on arrival.
Rules verified July 2026 via fwp.mt.gov. More: Montana state parks guide · Dog rules in all 50 states compared
Park Location
Plan your gear for Tongue River Reservoir State Park
From our editorial guides, matched to this park’s activities:
