Big Springs, Island Park, Idaho 83429

## Overview Big Springs is one of the largest natural springs in the United States and serves as a primary headwater of Henry's Fork of the Snake River. Located in the Island Park area of eastern Idaho within the Caribou-Targhee National Forest, this remarkable spring produces an estimated 120 million gallons of crystal-clear water per day at a near-constant temperature of around 52°F (11°C). The water emerges from porous volcanic rock — a legacy of the region's volcanic geology closely tied to the Yellowstone hotspot — creating a stunning, glassy pool that feeds directly into the Henry's Fork. Big Springs has long been a beloved destination in Fremont County. The spring and its surrounding area are managed by the U.S. Forest Service, and the site includes a short boardwalk and viewing bridge that offer visitors a spectacular look at the massive rainbow and brown trout that congregate in the gin-clear water below. These fish are famously visible from the bridge, and visitors have traditionally enjoyed watching (and feeding) them, though feeding practices may be subject to local regulations. Nearby, visitors can explore the historic Johnny Sack Cabin, a beautifully hand-crafted log cabin built in the 1930s by German immigrant John "Johnny Sack" Sackman, who lived beside the spring for decades. The cabin is listed on the National Register of Historic Places and is open for tours during the summer months, adding a layer of cultural and historical richness to any visit. While the water flowing from Big Springs has historically been regarded as exceptionally pure and clean, and the spring has been described as a source of pristine water, visitors should be aware that no guarantees of potability can be made without current testing. ## Directions 1. From the town of Macks Inn, Idaho (along US-20), turn east onto Big Springs Loop Road (Forest Road 059). 2. Follow Big Springs Loop Road for approximately 4 to 5 miles as it winds through the forest. 3. Watch for signs indicating the Big Springs parking area and trailhead on your right. 4. Park in the designated lot and follow the short paved path and boardwalk to the spring and viewing bridge. The site is well-signed from US-20 and is typically accessible from late spring through early fall, depending on snowpack and road conditions. Winter access may be limited. ## What to Expect Upon arrival, a short, accessible boardwalk leads from the parking area to the spring itself. The water is strikingly clear — visibility extends to the bottom of the pool, where you can observe large trout hovering in the current. A wooden bridge spans the outflow, providing an excellent vantage point for viewing the fish and the turquoise-tinted water. The surrounding landscape is classic high-elevation Idaho forest — lodgepole pines, wildflowers in summer, and abundant wildlife. Moose, bald eagles, trumpeter swans, and osprey are frequently spotted in the area. The Big Springs Water Trail, a gentle canoe or kayak route, begins at the spring and follows the crystal-clear waterway downstream — a popular activity during warmer months. The Johnny Sack Cabin is located just steps from the spring and is well worth a visit. Interpretive signs throughout the area provide context about the spring's geology, the local ecosystem, and the cabin's history. Big Springs is a day-use area with no camping directly at the site, though several Forest Service campgrounds are located nearby along the Big Springs Loop Road. Restroom facilities are available at the parking area. The boardwalk and viewing areas are generally accessible, though conditions may vary. The site is most popular from June through September, with peak visitation in July and August.