Island Park Reservoir Montana Fishing, Camping, Boating

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Island Park Reservoir

Island Park Reservoir holds many wonders of nature for visitors who love to get out in the wilds for some challenging fishing with a backdrop of the Targhee National Forest.

  • Enjoy the beautiful setting of pines and wildflowers at Island Park Reservoir
  • Only 28 miles south of West Yellowstone
  • Catch some big rainbow, cutthroat and hybrid trout
  • Go water skiing or float a tube in the mountain waters
  • Spot some of the abundant wildlife as you enjoy your outdoor recreation


Island Park Reservoir is just south of West Yellowstone, in a beautiful setting of pine trees and wildflowers. It’s a great destination for stillwater fishing and relaxing boating excursions.


Island Park Reservoir is located just west of Island Park, Idaho, off Highway 20, 30 miles north of Ashton and 28 miles south of West Yellowstone, Montana.


Island Park Reservoir is accessible the year round.


This 7,000-acre reservoir is a popular place for both locals and visitors to get out in the sun for some fabulous water sports.

You can fish in the summer or winter here at Island Park Reservoir, with a decent fish population making catches of big rainbow (up to 12 pounds), cutthroat and hybrid trout a real treat. You’ll also find brook trout, salmon and whitefish.

Boating and other Water Sports
Here is a perfect place to launch your boat, from any one of the 5 boat launches on the reservoir. You can bring your own boat, hire one with a guide service or get a float tube. Try water skiing around the lake or pull a tube. The choice is yours!

Fuel is also available as well as plenty of parking.

Camping out at the reservoir is a wonderful experience for the whole family. You will find a campground right at the shore, close to a boat ramp and small grocery store. RVs are also allowed. There are a number of campgrounds in the surrounding forest and you’ll have your choice of great settings.

Wildlife Viewing
Wildlife is abundant around the reservoir and you might spot an elk, moose, bear or even a bison.

Additional Info

The Island Park area is actually a crater that is 23 miles in diameter. A volcano collapsed many thousands of years ago, creating this caldera. The south bank of the Island Park Reservoir is formed by the caldera’s northern slope.

The dam that created the reservoir was built in 1937 to provide for crop irrigation at the head of Box Canyon.

Other Island Park Reservoir Resources

Ennis Lake

Reservoir on the Madison River near Ennis Montana.