At an approximate elevation of , it enters the Snake River, the Idaho-Oregon border, west of Parma and three miles (5 km) south of Nyssa, Oregon. The river was called "Reed's River" in the early 19th century, named after Pacific Fur Company employee John Reed, who explored parts of the river throughout 1813 and 1814. The river is diverted to canals for irrigation on the plain west of Boise. The dams that form the mountain reservoirs were constructed as part of the Bureau of Reclamation's "Boise Project" to provide agricultural irrigation, hydroelectricity, drinking water, and flood control to Boise and the Treasure Valley. The major projects' initial completion dates were:   The river is a popular destination for floating, specifically on the urban tree-lined run through Boise during hot, dry summer afternoons. Tubers and floaters launch at Barber Park and land at Ann Morrison Park, between major irrigation diversion dams. Several minor diversion weirs are passed as well as several bridges on the trip. Water skiing is popular above the dam at the Lucky Peak Reservoir. On the lower (warmwater) course of the river, low summer flows and poorer water quality from agricultural runoff limit fishery production. This section of river supports a fair fishery for largemouth bass, smallmouth bass, and channel catfish. Upstream from Star, the river is a coldwater stream and supports a greater variety of fish. The most prevalent species on this section is mountain whitefish, as well as hatchery-reared rainbow trout, wild rainbow trout, and fingerling brown trout. Upstream from Lucky Peak and Arrowrock reservoirs, the river and its tributaries contain excellent populations of wild rainbow trout, mountain whitefish, and bull trout. This is especially true immediately downstream from the outflow of Anderson Ranch reservoir, where the South Fork takes on the characteristics of a classic "tailwater" for over from the put-in below the dam to Cow Creek Bridge. The Boise River is also popular for fishing, mostly for rainbow trout and, in the winter, steelhead. Spin-fishermen use roostertail spinners and bait such as worms and Powerbait, while fly fishermen use a variety of flies mimicking the abundant aquatic and terrestrial insects present in the watershed, as well as streamers.