Anderson Ranch Reservoir fills a long mountain valley on the South Fork Boise River in Elmore County, Idaho, northeast of Mountain Home. The lake is roughly 14 miles long and about a mile wide, with around 50 miles of shoreline and water more than 300 feet deep near the dam. Anderson Ranch Dam, an earth and rockfill structure 456 feet high, was started by the Bureau of Reclamation in 1941 and finished in 1950, when it was the tallest dam of its type in the world. Its main job is storing irrigation water for the Boise Project, with a 40 megawatt powerplant at its base. The Boise National Forest's Mountain Home Ranger District runs the campgrounds and boat ramps around the shore.

This listing is pinned on the Fall Creek Boat Ramp, a concrete launch on the reservoir's west shore. The Forest Service lists it as a no-fee site with a vault toilet and no drinking water, open from about May 15 to October 1 or until snow closes the roads. It has a boarding dock and a large parking area, and Fall Creek Resort across the road sells supplies. The Forest Service also lists swimming here, but this is a boat launch with no designated beach or lifeguard, so swimmers should stay well clear of the ramp lane. Two campgrounds the Forest Service lists as no-fee sit a short drive south along the same shore road: Castle Creek and Evans Creek, which has fire rings, picnic tables and a vault toilet.

Getting there takes some gravel. From Mountain Home, drive about 21 miles on US 20 to Forest Road 134, follow it about 6 miles to Anderson Ranch Dam, then turn onto Forest Road 120 and follow the west shore northeast past Evans Creek and Castle Creek. Plan on about an hour and twenty minutes from Mountain Home. The other approach leaves US 20 on the paved Pine-Featherville road (Forest Highway 61), which runs up the east side of the lake to the small community of Pine at the upper end. From Pine, Forest Roads 128, 113 and 120 wind back down the west shore to Fall Creek, about 10 miles.

Other access points are spread around the lake. Curlew Creek, on the Pine-Featherville road about 14 miles north of US 20, has a boat ramp, dock, drinking water, and 18 day-use sites next to its campground. Pine Campground has a concrete ramp and dock near the head of the reservoir. Deer Creek Boat Ramp has a small dirt lot for about 15 vehicles and charges a $3 per vehicle day-use fee. Fees and seasons differ from site to site, so check each Forest Service page before you go.

Fishing is the main draw. Idaho Fish and Game manages Anderson Ranch mostly as a kokanee fishery and stocks kokanee every spring. After slow years from 2020 to 2022, strong year classes in 2023 through 2025 brought catch rates back up, and the department's 2026 outlook expects plenty of kokanee in the 10 to 13 inch range. Kokanee season usually starts in mid to late April with fish shallow, from 1 to 15 feet down. By summer, most anglers run downriggers at 35 to 80 feet. The lake also holds smallmouth bass, rainbow trout, yellow perch, bull trout and some fall chinook, and the river below the dam is a known fly fishing stretch for rainbow trout.

Boaters, water skiers and personal watercraft share the lake on summer weekends, so paddlers in kayaks and canoes do best in the quieter coves near Fall Creek and Castle Creek, especially early in the day before boat traffic builds. Because the reservoir is run for irrigation, the water level drops through the summer and fall, and the ends of some ramps can end up high and dry in low-water years. Check current storage on Reclamation's Boise River water data before hauling a boat up. In late summer, it is also worth checking Idaho DEQ's cyanobacteria advisories before swimming.

Big changes are planned for the dam. Reclamation and the Idaho Water Resource Board plan to raise Anderson Ranch Dam by six feet, adding roughly 29,000 acre-feet of storage. Final designs for the dam raise and the reservoir rim work were finished in March 2026. The rim work covers erosion control, recreation facilities and the Pine airstrip. Environmental review is expected to wrap up in late 2026 or early 2027, with construction contracting to follow through 2027. Once work begins, Reclamation expects a temporary detour across the dam and some full closures of the dam road, so watch for notices if you plan to come in from the dam side.