12,796 people (2024 Census estimate, −2.2% since 2020)
4,998 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.
5 active community water systems list Big Horn County in the area they serve, reporting 4,605 people served in all (a system that crosses county lines counts its whole population).
| HARDIN CITY OF surface water · local government · MT0000235 | 3,500 served |
| LODGE GRASS TOWN OF groundwater · local government · MT0000277 | 480 served |
| FORT SMITH WATER AND SEWER DISTRICT groundwater · local government · MT0004765 | 450 served |
| YELLOWTAIL DAM GC SYSTEM groundwater · federal · MT0002514 | 125 served |
| WEGNER WATER SERVICE HAULER buys surface water · private · MT0003590 | 50 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 34 people were held in Big Horn County's jail, in Vera's latest figure (2021), or 445 per 100,000 residents ages 15–64. In 2016 it was about 45.
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.
8 school districts have their office in Big Horn County. School taxes are usually the largest part of a property tax bill.
Spent $27.5 million — $22 million to run schools, about $17,138 per student, plus $4.9 million on buildings and equipment. Money in: $4.2 million local (mostly property tax), $8.2 million state, $15.5 million federal. Long-term debt: $4.6 million.
Spent $8.3 million — $6.9 million to run schools, about $13,494 per student, plus $360,000 on buildings and equipment. Money in: $3.1 million local (mostly property tax), $3.6 million state, $3 million federal. Long-term debt: $8.2 million.
Spent $5.8 million — $5.2 million to run schools, about $18,982 per student, plus $622,000 on buildings and equipment. Money in: $352,000 local (mostly property tax), $1.7 million state, $3.6 million federal.
Spent $5.2 million — $4.4 million to run schools, about $25,645 per student, plus $776,000 on buildings and equipment. Money in: $733,000 local (mostly property tax), $1.5 million state, $2.4 million federal.
Spent $5.6 million — $2.3 million to run schools, about $25,693 per student, plus $3.3 million on buildings and equipment. Money in: $381,000 local (mostly property tax), $710,000 state, $4.4 million federal. Long-term debt: $9,000.
Spent $2.5 million — $2 million to run schools, about $27,521 per student, plus $540,000 on buildings and equipment. Money in: $391,000 local (mostly property tax), $643,000 state, $1.7 million federal. Long-term debt: $11,000.
Spent $2 million — $1.9 million to run schools, about $32,362 per student, plus $140,000 on buildings and equipment. Money in: $555,000 local (mostly property tax), $801,000 state, $1.4 million federal. Long-term debt: $34,000.
Spent $258,000 — $207,000 to run schools, about $29,571 per student, plus $27,000 on buildings and equipment. Money in: $129,000 local (mostly property tax), $61,000 state, $79,000 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: Relatively Low compared with other U.S. counties. FEMA estimates natural hazards cost Big Horn County about $11.2 million a year on average in buildings, crops and lives. Ability to bounce back (community resilience): Very Low; social vulnerability: Very High.
Source: FEMA National Risk Index (December 2025), expected annual loss. Ratings compare counties nationwide; they're estimates, not predictions.
133 bridges in Big Horn County: 38 in good condition, 90 fair, and 5 poor (3.8%). “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.
| OLD HWY 87 over TWO LEGGINS CANAL 0 · built 1931 | 564 vehicles a day |
| BATTLEFIELD ROAD over MEDICINE TAIL COULEE · built 1938 | 150 vehicles a day |
| SOAP CREEK RD over BIG HORN CANAL 009 · built 1946 | 63 vehicles a day |
| IRR BIA RTE 205 over UPPER LODGE GRASS CREEK · built 1994 | 12 vehicles a day |
| IRR BIA RTE 226 over BLACK CANYON CREEK · built 1965 | 5 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $49.2 million of work in Big Horn County in fiscal 2025, about $3,747 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 Montana 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 Big Horn 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 Big Horn County built: brayden.ozark@gmail.com.
More of Montana: the state government and every county in Montana.
Nearby counties: Yellowstone County (52 mi) · Sheridan County, WY (53 mi) · Treasure County (58 mi) · Big Horn County, WY (65 mi) · Rosebud County (67 mi) · Carbon County (74 mi).