55,549 people (2024 Census estimate, +5.0% since 2020)
469 square miles of land · 118 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.
7 active community water systems list Madison County in the area they serve, reporting 43,820 people served in all (a system that crosses county lines counts its whole population).
| REXBURG CITY OF groundwater · local government · ID7330022 | 40,695 served |
| SUGAR CITY CITY OF groundwater · local government · ID7330026 | 2,395 served |
| LIBERTY ESTATES groundwater · private · ID7330065 | 300 served |
| CEDAR BUTTE SUBDIVISION groundwater · private · ID7330067 | 300 served |
| HILLVIEW SUBD groundwater · private · ID7330011 | 50 served |
| MEADOW LARK COURT LLC groundwater · private · ID7330014 | 45 served |
| SYRINGA PARK SUBD groundwater · private · ID7330028 | 35 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 50 people were held in Madison County's jail, in Vera's latest figure (2019), or 125 per 100,000 residents ages 15–64. In 2014 it was about 68.
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 Madison County. School taxes are usually the largest part of a property tax bill.
Spent $53.6 million — $48.5 million to run schools, about $8,423 per student, plus $2.4 million on buildings and equipment. Money in: $16.2 million local (mostly property tax), $38.9 million state, $10.2 million federal. Long-term debt: $64.7 million.
Spent $15.9 million — $15 million to run schools, about $7,631 per student, plus $204,000 on buildings and equipment. Money in: $3.4 million local (mostly property tax), $13.5 million state, $1.8 million federal. Long-term debt: $13 million.
Spent $7.9 million — $7.2 million to run schools, about $11,830 per student, plus $688,000 on buildings and equipment. Money in: $1.6 million local (mostly property tax), $5.4 million state, $1.1 million 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: Relatively Low compared with other U.S. counties. FEMA estimates natural hazards cost Madison County about $22.5 million a year on average in buildings, crops and lives. Ability to bounce back (community resilience): Relatively Moderate; social vulnerability: Relatively Low.
Source: FEMA National Risk Index (December 2025), expected annual loss. Ratings compare counties nationwide; they're estimates, not predictions.
80 bridges in Madison County: 26 in good condition, 54 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 $10.3 million of work in Madison County in fiscal 2025, about $194 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 Madison 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 Madison County built: brayden.ozark@gmail.com.
More of Idaho: the state government and every county in Idaho.
Nearby counties: Teton County (22 mi) · Bonneville County (27 mi) · Fremont County (31 mi) · Jefferson County (33 mi) · Clark County (49 mi) · Bingham County (54 mi).