72,557 people (2024 Census estimate, +0.8% since 2020)
610 square miles of land · 119 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.
12 active community water systems list Riley County in the area they serve, reporting 62,626 people served in all (a system that crosses county lines counts its whole population).
| MANHATTAN, CITY OF groundwater · local government · KS2016112 | 54,763 served |
| RILEY CO RWD 1 buys groundwater · local government · KS2016135 | 2,108 served |
| OGDEN, CITY OF groundwater · local government · KS2016128 | 1,721 served |
| COLONIAL GARDENS MOBILE HOME CT buys groundwater · private · KS2016118 | 1,200 served |
| RILEY, CITY OF groundwater · local government · KS2016124 | 977 served |
| RIVERCHASE MOBILE HOME PARK groundwater · private · KS2016119 | 460 served |
| LEONARDVILLE, CITY OF groundwater · local government · KS2016120 | 436 served |
| KONZA VALLEY WATER BENEFIT DISTRICT buys groundwater · private · KS2016109 | 345 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 66 people were held in Riley County's jail, in Vera's latest figure (2019), or 120 per 100,000 residents ages 15–64. In 2013 it was about 76.
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 Riley County. School taxes are usually the largest part of a property tax bill.
Spent $133.1 million — $95 million to run schools, about $13,450 per student, plus $31.4 million on buildings and equipment. Money in: $41.5 million local (mostly property tax), $63.7 million state, $13.3 million federal. Long-term debt: $230.3 million.
Spent $10.3 million — $9.2 million to run schools, about $12,925 per student, plus $633,000 on buildings and equipment. Money in: $3.8 million local (mostly property tax), $7.3 million state, $1 million federal. Long-term debt: $14.1 million.
Spent $4.8 million — $4.4 million to run schools, about $16,472 per student, plus $273,000 on buildings and equipment. Money in: $1.7 million local (mostly property tax), $2.8 million state, $254,000 federal. Long-term debt: $3.8 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 Riley County about $29.4 million a year on average in buildings, crops and lives. Ability to bounce back (community resilience): Relatively High; social vulnerability: Very Low.
Source: FEMA National Risk Index (December 2025), expected annual loss. Ratings compare counties nationwide; they're estimates, not predictions.
225 bridges in Riley County: 128 in good condition, 87 fair, and 10 poor (4.4%). “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.
| RS 578 G.3-9.0 over CROOKED CREEK · built 1925 | 325 vehicles a day |
| W. KS AV G.4-18.5C over WILDCAT CREEK · built 1920 | 70 vehicles a day |
| LOCAL K.0-14.3T over MILL CREEK · built 1920 | 45 vehicles a day |
| LOCAL K.0-16.4 over MILL CREEK · built 1945 | 30 vehicles a day |
| LOCAL P.1-18.3C over MILL CREEK · built 1920 | 20 vehicles a day |
| LASITA R B.0-17.9T over TIMBER CREEK · built 1930 | 10 vehicles a day |
Source: Federal Highway Administration, National Bridge Inventory (2025 submission). Includes state, county and city bridges.
Federal grants paid for $87.4 million of work in Riley County in fiscal 2025, about $1,214 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 Kansas 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 Riley 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 Riley County built: brayden.ozark@gmail.com.
More of Kansas: the state government and every county in Kansas.
Nearby counties: Geary County (20 mi) · Pottawatomie County (22 mi) · Clay County (24 mi) · Marshall County (36 mi) · Wabaunsee County (36 mi) · Dickinson County (37 mi).