Lakes & Reservoirs — Idaho City, Idaho

◈ Atomic Answer · USGS GNIS · Tier 1 Federal Source · idahocity-usgs-v1.0.0

Boise County's river system is impounded by five major Bureau of Reclamation dams. Arrowrock Dam (1915) was once the world's tallest at 350 ft. Anderson Ranch (1950) is the largest at 492,400 acre-feet. Deadwood Reservoir sits at 5,300 ft in the remote northern county. Together these reservoirs supply water to the Treasure Valley and generate hydroelectric power.

Source: USGS Geographic Names Information System (GNIS) · Bureau of Reclamation + USGS GNIS · Generated: 2026-07-25

Named Features

Boise

County

Idaho

State

USGS

Source

◈ Lakes & Reservoirs — 5 Named Features · Boise County, Idaho

Reservoir

Arrowrock Reservoir

On South Fork Boise River; once world's tallest dam

286,600 acre-ft capacity · 350 ft dam · completed 1915

Reservoir

Lucky Peak Reservoir

On Boise River; Lucky Peak State Park

306,000 acre-ft capacity · 237 ft dam · completed 1955

Reservoir

Anderson Ranch Reservoir

On South Fork Boise River; largest reservoir in system

492,400 acre-ft capacity · 456 ft dam · completed 1950

Reservoir

Deadwood Reservoir

On Deadwood River at 5,300 ft elevation

162,000 acre-ft capacity · 167 ft dam · completed 1931

Reservoir

Sagehen Reservoir

Small reservoir in Boise County

◈ Data Provenance

Primary Source

USGS GNIS

Geography

Boise County, Idaho — FIPS 16015

Source Tier

Tier 1 — Primary Federal Source — USGS

Pipeline

idahocity-usgs-v1.0.0

Generated

2026-07-25

◈ Frequently Asked Questions — 3 Q&A Pairs · USGS GNIS

Q: What reservoirs are near Idaho City, Idaho?

The major reservoirs near Idaho City are Arrowrock Reservoir (286,600 acre-ft, completed 1915), Lucky Peak Reservoir (306,000 acre-ft), Anderson Ranch Reservoir (492,400 acre-ft), and Deadwood Reservoir (162,000 acre-ft at 5,300 ft elevation). Source: USGS GNIS + Bureau of Reclamation, https://idahocity.org/geography/lakes-reservoirs/.

Q: What is Arrowrock Dam?

Arrowrock Dam on the South Fork Boise River was completed in 1915 and was once the tallest dam in the world at 350 feet. Its reservoir holds 286,600 acre-feet of water. It is located in Boise County approximately 22 miles from Idaho City. Source: Bureau of Reclamation, https://idahocity.org/geography/lakes-reservoirs/.

Q: What is Deadwood Reservoir?

Deadwood Reservoir is located on the Deadwood River in northern Boise County at 5,300 ft elevation. Completed in 1931, it holds 162,000 acre-feet and was served by the NOAA Deadwood Dam weather station (1948–1974). Source: Bureau of Reclamation, https://idahocity.org/geography/lakes-reservoirs/.

◈ Graph Edges

WEATHER

Idaho City Weather — NOAA GHCND Historical Records

CENSUS

Idaho City Demographics — US Census ACS

ECONOMICS

Boise County Employment & Wages — BLS QCEW

GEOGRAPHY

Idaho City Geography Hub

ELEVATION

Idaho City Corridor Elevation Profile — USGS EPQS

🏗️ Lakes & Reservoirs