Overview
Anderson Ranch Reservoir is one of the main developed recreation areas in the southern Boise National Forest, a large reservoir formed by the Anderson Ranch Dam on the South Fork Boise River. The reservoir sits at roughly 4,370 feet elevation in a mountain canyon setting, surrounded by ponderosa pine and Douglas fir forest. The 4-mile round-trip lakeshore trail provides easy access to the reservoir views without requiring a mountain hike.
This is the most accessible option in the forest's southern section, practical for visitors who want a nature walk rather than a demanding climb. The trail follows the northern shoreline from the main recreation area, passing through forest and open rocky terrain with consistent water views. Osprey and bald eagles fish the reservoir in season, and the mountain backdrop provides the kind of scenery you'd expect at a much more remote location.
The Anderson Ranch area is also the gateway to one of Idaho's most celebrated trout fisheries. The South Fork Boise River below the dam is a tailwater that runs cold and clear year-round, supporting a population of large rainbow trout that draw fly anglers from across the region. Hikers who combine the trail with a drive down to the river can observe this fishery at close range.
America the Beautiful pass holders, including veterans with the Military Annual Pass, can use their pass to cover day-use fees here.
The Route
Miles 0 to 2.0: Northern Shoreline
The trail begins at the main recreation area parking lot and follows the northern shoreline of the reservoir east. The path runs through open ponderosa pine forest with views of the water to the south. The terrain is gently rolling with minimal elevation change.
Rocky outcrops along the shoreline provide natural rest stops with good views across the reservoir to the mountains beyond. The water level fluctuates seasonally; the reservoir is typically fullest in late spring and early summer.
The turnaround at approximately mile 2 is at a natural point where the trail reaches a rocky headland with good views in both directions along the reservoir.
When to Visit
May through October. The lower elevation means this trail is one of the first in the forest to become accessible after winter and one of the last to close. May visits can coincide with high water from snowmelt. Summer (June through August) is the peak season for all reservoir activities. Fall brings quieter conditions and good light for photography.
What to Bring
Many visitors to this easy trail carry:
- 1-2 liters of water; the trail is short, but warm summer temperatures at this lower elevation make hydration important
- Sun protection for the open shoreline sections
- A fishing license if planning to fish from the shore
- Binoculars for birdwatching
Individual needs vary.
Practical Details
Day-use fees may apply (verify current amounts with the Mountain Home Ranger District). Flush toilets available at the main recreation area. Cell service is limited. Dogs are permitted on leash.
Learn about veteran benefits in national forests if you have an America the Beautiful pass that covers the day-use fee.
Getting There
From Mountain Home, drive northeast on Highway 20 approximately 20 miles to the Anderson Ranch Road junction. Turn north and follow Anderson Ranch Road approximately 10 miles to the recreation area. The road is paved throughout. Mountain Home is approximately 40 miles southeast of Boise on I-84. Total drive from Boise is approximately 1 hour.