265,514 people (2024 Census estimate, +1.6% since 2020)
437 square miles of land · 607 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.
17 active community water systems list Harford County in the area they serve, reporting 168,811 people served in all (a system that crosses county lines counts its whole population).
| HARFORD COUNTY D.P.W. surface water · local government · MD0120016 | 104,567 served |
| CITY OF ABERDEEN buys surface water · local government · MD0120001 | 18,006 served |
| CHAPEL HILL - ABERDEEN PROVING GROUNDS groundwater · local government · MD0120002 | 15,000 served |
| CITY OF HAVRE DE GRACE surface water · local government · MD0120012 | 14,000 served |
| MARYLAND AMERICAN WATER COMPANY surface water · private · MD0120003 | 13,200 served |
| MD AMERICAN WATER GREENRIDGE buys surface water · private · MD0120011 | 2,351 served |
| SWAN HARBOUR DELL MOBILE HOME PARK groundwater · private · MD0120215 | 500 served |
| CAMPUS HILLS WATER WORKS groundwater · private · MD0120007 | 250 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 315 people were held in Harford County's jail, in Vera's latest figure (2024), or 186 per 100,000 residents ages 15–64. In 2019 it was about 355.
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 Harford County. School taxes are usually the largest part of a property tax bill.
Spent $735.7 million — $665.4 million to run schools, about $17,493 per student, plus $41.8 million on buildings and equipment. Money in: $411 million local (mostly property tax), $300.8 million state, $63.2 million federal. Long-term debt: $318.2 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 Harford County about $51.4 million a year on average in buildings, crops and lives. Ability to bounce back (community resilience): Very High; social vulnerability: Very Low.
Source: FEMA National Risk Index (December 2025), expected annual loss. Ratings compare counties nationwide; they're estimates, not predictions.
276 bridges in Harford County: 107 in good condition, 157 fair, and 12 poor (4.3%). “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.
| US 1 over WINTERS RUN · built 1963 | 21,112 vehicles a day |
| US 1 over N TOLLGATE RD PED TRAIL · built 1963 | 20,542 vehicles a day |
| ABINGDON ROAD over CSX RAILROAD · built 1940 | 10,242 vehicles a day |
| JARRETTSVILLE ROAD over EAST BRANCH /WINTERS RUN · built 1950 | 4,308 vehicles a day |
| HOOKERS MILL ROAD over BYNUM RUN · built 1957 | 3,986 vehicles a day |
| MD 136 over FALLING BRANCH · built 1931 | 2,161 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $72.2 million of work in Harford County in fiscal 2025, about $277 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 Maryland 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 Harford 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 Harford County built: brayden.ozark@gmail.com.
More of Maryland: the state government and every county in Maryland.
Nearby counties: Baltimore County (18 mi) · Cecil County (19 mi) · Kent County (22 mi) · Baltimore city (23 mi) · Lancaster County, PA (35 mi) · New Castle County, DE (35 mi).