25,976 people (2024 Census estimate, +4.9% since 2020)
2,566 square miles of land · 10 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.
13 active community water systems list Cassia County in the area they serve, reporting 12,913 people served in all (a system that crosses county lines counts its whole population).
| BURLEY WATER DEPT groundwater · private · ID5160008 | 10,345 served |
| OAKLEY CITY OF groundwater · local government · ID5160035 | 821 served |
| OAKLEY VALLEY WATER CORPORATION groundwater · private · ID5160031 | 500 served |
| DECLO CITY OF groundwater · local government · ID5160012 | 350 served |
| ALBION CITY OF groundwater · local government · ID5160001 | 325 served |
| OVERLOOK MOBILE HOME VILLAGE groundwater · private · ID5160037 | 120 served |
| VIEW WATER DEVELOPMENT COMPANY groundwater · private · ID5160043 | 112 served |
| GOLDEN RAIL TRAILER COURT groundwater · private · ID5160017 | 70 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 81 people were held in Cassia County's jail, in Vera's latest figure (2023), or 522 per 100,000 residents ages 15–64. In 2018 it was about 88.
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 Cassia County. School taxes are usually the largest part of a property tax bill.
Spent $55.9 million — $52.4 million to run schools, about $9,415 per student, plus $2.4 million on buildings and equipment. Money in: $8.9 million local (mostly property tax), $41.4 million state, $8.8 million federal. Long-term debt: $25 million.
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: Relatively Low compared with other U.S. counties. FEMA estimates natural hazards cost Cassia County about $15.6 million a year on average in buildings, crops and lives. Ability to bounce back (community resilience): Relatively Low; social vulnerability: Relatively Low.
Source: FEMA National Risk Index (December 2025), expected annual loss. Ratings compare counties nationwide; they're estimates, not predictions.
117 bridges in Cassia County: 24 in good condition, 93 fair, and 0 poor (0.0%). “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.
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $15.7 million of work in Cassia County in fiscal 2025, about $637 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 Cassia 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 Cassia County built: brayden.ozark@gmail.com.
More of Idaho: the state government and every county in Idaho.
Nearby counties: Minidoka County (40 mi) · Jerome County (43 mi) · Power County (49 mi) · Twin Falls County (53 mi) · Box Elder County, UT (54 mi) · Lincoln County (56 mi).