3,113 people (2024 Census estimate, −3.6% since 2020)
953 square miles of land · 3 people per square mile
“Highest” and “lowest” are just order, not grades: a high rank for poverty or hazard losses means more of it. Each figure's source is in its section below.
8 active community water systems list Sierra County in the area they serve, reporting 3,037 people served in all (a system that crosses county lines counts its whole population).
| CITY OF LOYALTON groundwater · local government · CA4610001 | 983 served |
| SIERRA CSA #5, SIERRA BROOKS groundwater · local government · CA4600009 | 726 served |
| SIERRA WATER RESOURCES - SIERRA CITY groundwater · private · CA4600017 | 324 served |
| DOWNIEVILLE PUBLIC U.D. surface water · local government · CA4610002 | 290 served |
| SIERRA CITY WATER WORKS, INC. groundwater · private · CA4600056 | 250 served |
| SIERRAVILLE P.U.D. groundwater · local government · CA4600018 | 200 served |
| SIERRA CO. W.W.D #1 CALPINE groundwater · local government · CA4600019 | 182 served |
| ALLEGHANY COUNTY W.D. groundwater · local government · CA4600012 | 82 served |
Source: U.S. EPA Safe Drinking Water Information System (SDWIS), active community systems, . Look up any system's violations and test results with EPA's search using its ID.
About 2 people were held in Sierra County's jail, in Vera's latest figure (2015), or 107 per 100,000 residents ages 15–64. In 2010 it was about 7.
Source: Vera Institute of Justice, Incarceration Trends (built from federal Bureau of Justice Statistics jail surveys). Counties without their own jail, or that share one, may show no figure.
1 school district has its office in Sierra County. School taxes are usually the largest part of a property tax bill.
Spent $8.1 million — $7.9 million to run schools, about $19,640 per student, plus $182,000 on buildings and equipment. Money in: $3.3 million local (mostly property tax), $4.4 million state, $802,000 federal.
Source: U.S. Census Bureau, 2023 Annual Survey of School System Finances. Districts are listed by the county of their main office; some serve neighboring counties too.
Source: County Health Rankings & Roadmaps 2025 (University of Wisconsin Population Health Institute), which gathers federal data (CDC, Census, and others); measures cover different recent years. Blank lines aren't reported for small counties.
Overall risk: Very Low compared with other U.S. counties. FEMA estimates natural hazards cost Sierra County about $8.4 million a year on average in buildings, crops and lives. Ability to bounce back (community resilience): Relatively Low; social vulnerability: Relatively High.
Source: FEMA National Risk Index (December 2025), expected annual loss. Ratings compare counties nationwide; they're estimates, not predictions.
66 bridges in Sierra County: 29 in good condition, 33 fair, and 4 poor (6.1%). “Poor” means a main part — the deck, the beams, or the supports — is rated 4 or lower on the federal 0–9 scale. It doesn't mean unsafe to drive; unsafe bridges are closed.
| RAILROAD AVENUE over EAST BRANCH SMITHNECK CR · built 1987 | 1,000 vehicles a day |
| WESTSIDE RD over SOUTH BRANCH CARMAN CRK · built 1950 | 670 vehicles a day |
| WESTSIDE RD over NORTH BRANCH CARMAN CRK · built 1950 | 670 vehicles a day |
| PACKER LAKE ROAD over SALMON CREEK · built 1960 | 200 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $3.8 million of work in Sierra County in fiscal 2025, about $1,164 per resident — to the county, cities, schools, hospitals, nonprofits and others.
Source: USAspending.gov, grants by place of performance, fiscal 2025 (Oct. 2024 to Sept. 2025). Search it by county to see each award.
From Grants.gov: posted grants listing county governments as eligible, soonest deadline first; research-only and overseas programs left out; list updated 2026-10-13, refreshed weekly. 62 are open in all. Cities, towns, school districts and nonprofits have their own lists there.
General election: Tuesday, November 3, 2026. Ballots mailed; drop boxes open: 2026-10-05. Last day to register to vote: 2026-10-19. Early in-person voting: 2026-10-24 to 2026-11-03. Election Day: 2026-11-03. Last day for mailed ballots to arrive: 2026-11-10.
Source: California Secretary of State — Nov. 3, 2026 key dates · California Official Voter Information Guide — dates to remember · California Secretary of State — make a plan to vote
The budget, property tax rates, audits, local officials and offices for Sierra County come from the county's own records, which we haven't gathered — not gathered, never hidden. See what a full county site looks like, or ask to have Sierra County built: brayden.ozark@gmail.com.
More of California: the state government and every county in California.
Nearby counties: Nevada County (23 mi) · Plumas County (33 mi) · Placer County (37 mi) · Yuba County (49 mi) · Carson City, NV (51 mi) · Storey County, NV (54 mi).