11,539 people (2024 Census estimate, +9.3% since 2020)
1,453 square miles of land · 8 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.
3 active community water systems list Washington County in the area they serve, reporting 6,109 people served in all (a system that crosses county lines counts its whole population).
| WEISER CITY OF surface water · local government · ID3440011 | 5,630 served |
| CAMBRIDGE CITY OF groundwater · local government · ID3440002 | 335 served |
| MIDVALE WATER SYSTEM groundwater · private · ID3440007 | 144 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 39 people were held in Washington County's jail, in Vera's latest figure (2021), or 635 per 100,000 residents ages 15–64. In 2016 it was about 35.
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.
3 school districts have their office in Washington County. School taxes are usually the largest part of a property tax bill.
Spent $16.5 million — $14.4 million to run schools, about $9,215 per student, plus $1.5 million on buildings and equipment. Money in: $2 million local (mostly property tax), $11.4 million state, $3.4 million federal.
Spent $2.5 million — $2.4 million to run schools, about $15,566 per student, plus $14,000 on buildings and equipment. Money in: $410,000 local (mostly property tax), $2 million state, $287,000 federal.
Spent $2.3 million — $2.1 million to run schools, about $14,067 per student, plus $47,000 on buildings and equipment. Money in: $590,000 local (mostly property tax), $2.1 million state, $272,000 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 Washington County about $7.5 million a year on average in buildings, crops and lives. Ability to bounce back (community resilience): Very Low; social vulnerability: Relatively High.
Source: FEMA National Risk Index (December 2025), expected annual loss. Ratings compare counties nationwide; they're estimates, not predictions.
80 bridges in Washington County: 26 in good condition, 50 fair, and 4 poor (5.0%). “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.
| STC 8217;COVE ROAD over WEISER RIVER · built 1917 | 490 vehicles a day |
| STC 3007;UNITY RD over WEISER RIVER · built 1910 | 180 vehicles a day |
| SAGE CREEK ROAD over SAGE CREEK · built 1965 | 50 vehicles a day |
| LOWER CRANE ROAD over CRANE CREEK · built 1955 | 20 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $18.3 million of work in Washington County in fiscal 2025, about $1,739 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.
Registration deadlines, early voting and polling places for Idaho are on the federal site vote.gov, which links to the state's official election office.
The budget, property tax rates, audits, local officials and offices for Washington 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 Washington County built: brayden.ozark@gmail.com.
More of Idaho: the state government and every county in Idaho.
Nearby counties: Payette County (31 mi) · Gem County (33 mi) · Adams County (34 mi) · Baker County, OR (47 mi) · Canyon County (57 mi) · Boise County (62 mi).