113,140 people (2024 Census estimate, −2.5% since 2020)
1,268 square miles of land · 89 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.
57 active community water systems list Jefferson County in the area they serve, reporting 114,507 people served in all (a system that crosses county lines counts its whole population).
| FORT DRUM buys surface water · federal · NY2212214 | 34,000 served |
| WATERTOWN CITY surface water · local government · NY2202346 | 27,861 served |
| LERAY TOWN WD 1, 2, 4 groundwater · local government · NY2221206 | 7,140 served |
| CARTHAGE VILLAGE surface water · local government · NY2202334 | 3,600 served |
| CAPE VINCENT TOWN WD 1 & 5 buys surface water · local government · NY2230018 | 2,600 served |
| SACKETS HARBOR VILLAGE surface water · local government · NY2202343 | 2,200 served |
| CLAYTON VILLAGE surface water · local government · NY2202335 | 2,100 served |
| ADAMS VILLAGE groundwater · local government · NY2202328 | 2,000 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 156 people were held in Jefferson County's jail, in Vera's latest figure (2026). In 2021 it was about 146.
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.
11 school districts have their office in Jefferson County. School taxes are usually the largest part of a property tax bill.
Spent $83.9 million — $76.7 million to run schools, about $19,480 per student, plus $3.4 million on buildings and equipment. Money in: $20.9 million local (mostly property tax), $58.2 million state, $13.3 million federal. Long-term debt: $18.6 million.
Spent $117 million — $87.5 million to run schools, about $25,009 per student, plus $25.2 million on buildings and equipment. Money in: $9.6 million local (mostly property tax), $63 million state, $33.9 million federal. Long-term debt: $35.5 million.
Spent $74.9 million — $64.1 million to run schools, about $22,026 per student, plus $9.8 million on buildings and equipment. Money in: $11.9 million local (mostly property tax), $50.7 million state, $17.4 million federal. Long-term debt: $1.4 million.
Spent $38.4 million — $34.8 million to run schools, about $18,948 per student, plus $1.7 million on buildings and equipment. Money in: $9.4 million local (mostly property tax), $30.5 million state, $4 million federal. Long-term debt: $7.5 million.
Spent $27.2 million — $26 million to run schools, about $18,551 per student, plus $637,000 on buildings and equipment. Money in: $9.2 million local (mostly property tax), $16.8 million state, $3.1 million federal. Long-term debt: $10.8 million.
Spent $28.1 million — $20.5 million to run schools, about $22,999 per student, plus $1.8 million on buildings and equipment. Money in: $12.2 million local (mostly property tax), $10.7 million state, $1.8 million federal. Long-term debt: $7.9 million.
Spent $12 million — $10.3 million to run schools, about $20,196 per student, plus $191,000 on buildings and equipment. Money in: $5 million local (mostly property tax), $6.2 million state, $1.4 million federal. Long-term debt: $5.8 million.
Spent $12.3 million — $10.4 million to run schools, about $20,638 per student, plus $540,000 on buildings and equipment. Money in: $4.4 million local (mostly property tax), $7 million state, $1.5 million federal. Long-term debt: $3 million.
And 3 more.
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 Jefferson County about $25.7 million a year on average in buildings, crops and lives. Ability to bounce back (community resilience): Relatively High; social vulnerability: Relatively Low.
Source: FEMA National Risk Index (December 2025), expected annual loss. Ratings compare counties nationwide; they're estimates, not predictions.
318 bridges in Jefferson County: 128 in good condition, 158 fair, and 32 poor (10.1%). “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.
| RTE I81 over SOUTH SANDY CREEK · built 1961 | 9,336 vehicles a day |
| RTE 342 over RTE I81 RTE I81 · built 1965 | 7,799 vehicles a day |
| RTE 971H over BLACK RIVER · built 1954 | 6,232 vehicles a day |
| RTE I81 over COUNTY ROAD 15 · built 1965 | 5,435 vehicles a day |
| RTE I81 over COUNTY ROAD 15 · built 1965 | 4,824 vehicles a day |
| RTE I81 over MULLET CREEK · built 1965 | 4,212 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $106.1 million of work in Jefferson County in fiscal 2025, about $909 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 New York 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 Jefferson 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 Jefferson County built: brayden.ozark@gmail.com.
More of New York: the state government and every county in New York.
Nearby counties: Lewis County (34 mi) · Oswego County (38 mi) · St. Lawrence County (59 mi) · Oneida County (60 mi) · Herkimer County (67 mi) · Onondaga County (69 mi).