Island Park, Yellowstone's Quiet Western Satellite town

A 36.8-mile Main Street (the world's longest) and a 23-mile diameter caldera (the world's largest) is Island Park's claim to fame.
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The Angler's Lodge and vacation homes line Henrys Fork in Island Park

The Angler's Lodge and vacation homes line Henrys Fork in Island Park

Twenty minutes from the West Entrance to Yellowstone National Park, Island Park in Idaho features a record-breaking main street and a number of natural areas to explore.

See the World's Longest Main Street

Island Park's Main Street runs parallel to Henry's Fork of the Snake River

Island Park's Main Street runs parallel to Henry's Fork of the Snake River

At 36.8 miles, Island Park's Main Street takes the cake for length. Back in 1947, local resorts and businesses incorporated a long strip of land along Highway 20 as the town of Island Park. This was because Idaho's liquor laws at the time prohibited the sale of liquor outside of a city's limits. It's also the reason the town varies from 500 to 5,000 feet in width. Today, the very long town has grown to be a base camp for outdoor recreation. You'll find many resorts, lodges, cabins and campgrounds a short drive from Yellowstone National Park.

Check Out the World's Largest Caldera

Two million years ago, an enormous volcano erupted in the area, emitting 2,500 times more ash than Mount St. Helens eruption in 1980. The remains of that ancient volcano formed a large caldera called the Island Park Caldera that actually stretches into Yellowstone National Park. The Island Park Caldera stretches 58 miles in one direction and 40 miles in the other, making it one of the world's largest calderas. A smaller, relatively newer caldera, which formed 1.3 million years ago, is 23 miles in diameter. It is nested inside of the Island Park Caldera and is referred to as the Henrys Fork Caldera. Today, it is covered in pine trees and wildflowers. It's a popular site for hiking and fishing in the summer and cross country skiing and snowmobiling in the winter.

Tour a Historic Cabin

Johnny Sack Cabin at Big Springs, Idaho

Johnny Sack Cabin at Big Springs, Idaho

While some may recognize the name "Johnny Sack" as that of the fictional crime boss of the Lupertazzi family in the HBO TV series The Sopranos, there's a former Island Park resident named Johnny Sack who's enjoyed a bit of fame in the decades since he died.

Standing at just 4 feet, 11 inches, Island Park resident Johnny Sack built a cabin near Big Springs in 1929, handcrafting an adjoining water wheel to run electricity to his cabin. His woodworking skills were so fine on both the cabin's exterior and interior that his property was placed on the National Register of Historic Places in 1979. To give an example, one of his ceiling lamps contains 72 individual pieces of wood. Visitors can tour his cabin between mid-June and mid-September from 10 a.m. to 4 p.m. daily. Donations are appreciated. The property is administered by the U.S. Forest Service.

Explore Harriman State Park and Wildlife Refuge

Great Blue Heron and Mallards at Silvermine Lake in Harriman State Park

Great Blue Heron and Mallards at Silvermine Lake in Harriman State Park

With more than 11,000 acres, nearby Harriman State Park and Wildlife Refuge is home to elk, moose, trumpeter swans and outstanding year-round recreational opportunities. From 1902-77, Union Pacific Railroad investors owned the land, which doubled as a cattle ranch and a vacation spot for the Guggenheim and Harriman families. These days, this beautiful spot is open to the public, and you can visit in the winter and snowshoe, Nordic ski or ride your fat bike on the park's 24 miles of groomed trails. In the summer, you can birdwatch, hike and ride horses there. Overnight accommodations include yurts, a bunkhouse, cabins and dorms.The Railroad Ranch Dormitory and Dining Hall are available for rent and accommodate groups of 15-40 people. The rustic log dormitory building is complimented by a modern dining facility where groups can cook for up to 40 people.

Fish in the Henrys Fork of the Snake River

Osprey at Henrys Fork of the Snake River in Idaho

A osprey at Henrys Fork

Famous for fly fishing, Henrys Fork stretches 127 miles as a tributary of the Snake River. It runs near town to form the 7,000 acre Island Park reservoir, popular for both anglers and boaters.

Big Springs, a spring in Island Park that releases more than 120 million gallons of water each day, is the source of Henrys Fork. Because of the spring's constant temperature of 52-degrees and its crystal clear flow, Henry's Fork is a favorite early season fishing spot when nearby rivers are cold and muddy. The Henrys Fork is known for its excellent trout fishing. The Big Spring Nature Trail, six miles north of the Island Park Ranger Station, is a half-mile, handicap-accessible trail. Visitors often see wildlife such as osprey, eagles, moose and deer from the trail.

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