Riley County is a county in Kansas, United States, about 50 miles west of Topeka along the Kansas River. It had a population of 71,959 at the 2020 census, an estimated 72,598 by 2025, and covers 622 square miles (1,610 km2) centred near 39°20′N 96°42′W.
Manhattan is the county seat and the county’s largest city; its postal code is 66502. The county holds 5 cities, one census-designated place and 7 unincorporated communities across 14 townships, and it runs on Central Time. Its FIPS code is 20161.
Towns & Villages in Riley County
Riley County has 13 named places on record: 5 incorporated cities, one census-designated place at Fort Riley, and 7 unincorporated communities with no local government of their own. CDP stands for census designated place; Unincorp. covers crossroads and small settlements with no formal boundary.
| Place | Type | Township | Pop. | ZIP |
|---|---|---|---|---|
| Manhattan | City · seat | Manhattan | 54,100 | 66502 |
| Fort Riley | CDP | — | 9,230 | 66442 |
| Riley | City | — | 938 | 66531 |
| Ogden | City | Ogden | 1,661 | 66517 |
| Leonardville | City | — | 432 | 66449 |
| Randolph | City | — | 159 | 66554 |
| Bala | Unincorp. | Bala | — | — |
| Zeandale | Unincorp. | Zeandale | — | — |
| Keats | Unincorp. | — | — | — |
| May Day | Unincorp. | May Day | — | — |
| Lasita | Unincorp. | — | — | — |
| Walsburg | Unincorp. | — | — | — |
| Winkler | Unincorp. | — | — | — |
Riley, the city, and Riley County share a namesake — Bennet C. Riley — but are not the same place; the city sits in the county’s northwest corner, well away from the seat at Manhattan. Randolph is not at its original site: the 1962 filling of Tuttle Creek Lake submerged the first townsite, and residents rebuilt on higher ground about a mile away, the only one of four flooded communities to relocate rather than disappear.
Townships
Riley County is divided into 14 townships — Ashland, Bala, Center, Fancy Creek, Grant, Jackson, Madison, Manhattan, May Day, Ogden, Sherman, Swede Creek, Wildcat and Zeandale — the legal minor civil divisions that predate most of the county’s incorporated cities. The Census Bureau does not publish a separate population figure for each Kansas township, so population is not shown below; each township’s namesake settlement, where one exists, is listed instead.
| Township | Pop. | Main settlement |
|---|---|---|
| Manhattan | — | Manhattan |
| Ogden | — | Ogden |
| Zeandale | — | Zeandale |
| Bala | — | Bala |
| May Day | — | May Day |
| Ashland | — | — |
| Center | — | — |
| Fancy Creek | — | — |
| Grant | — | — |
| Jackson | — | — |
| Madison | — | — |
| Sherman | — | — |
| Swede Creek | — | — |
| Wildcat | — | — |
ZIP Codes
- 66502 — Manhattan (also serves 66503, 66505 and 66506, covering Kansas State University and outlying Manhattan addresses)
- 66442 — Fort Riley
- 66531 — Riley
- 66517 — Ogden
- 66449 — Leonardville
- 66554 — Randolph
Bala, Keats, Lasita, May Day, Walsburg, Winkler and Zeandale have no ZIP code of their own; mail there is delivered under Manhattan’s or Riley’s code depending on location.
Geography
Riley County sits in the Flint Hills, a belt of limestone-capped tallgrass prairie hills in north-central Kansas. Of its 622 square miles, 610 are land and 12 are water, about 2.0 percent, most of it Tuttle Creek Lake. The lake formed in the 1960s when the Big Blue River was dammed along the county’s eastern edge, and it submerged four communities — Cleburne, Garrison Cross, Randolph and Stockdale — when it filled in 1962; only Randolph rebuilt, on higher ground nearby.
Marshall County lies to the northeast, Pottawatomie County to the east, Wabaunsee County to the southeast, Geary County to the south, Clay County to the west, and Washington County to the northwest. Marshall County, Pottawatomie County, Wabaunsee County, Geary County, Clay County and Washington County all border Riley directly.
Demographics
Riley County had a population of 71,959 at the 2020 census, and the latest estimate puts the county near 72,598 residents. Manhattan and Fort Riley are by far the two largest communities, together holding roughly nine in ten county residents. Median household income runs $61,098 (2024 estimate), below Kansas’s statewide figure of $70,333 (2023 ACS), a gap driven in part by Kansas State University’s large student population and its part-time and stipend earnings. Population density works out to roughly 118 people per square mile of land. The county’s age profile is unusually young: residents aged 15 to 34 make up more than half the population, one of the highest shares of any US county, reflecting the university and Fort Riley’s soldier population.
Economy & Local Life
Educational services employ the most workers in the county, about 8,729 people, followed by health care and social assistance at 4,292 and retail trade at 3,684. Kansas State University, with nearly 24,000 students, is Manhattan’s largest single employer and the county’s dominant institution. Fort Riley, home to the Army’s 1st Infantry Division on roughly 100,000 acres straddling the Riley-Geary county line, employs more than 3,500 civilians who live in the county, on top of its soldier population. Ascension Via Christi Hospital, Parker Hannifin and CivicPlus are among Manhattan’s other major employers. Kansas State University’s football season each autumn, centred on Bill Snyder Family Stadium, is the county’s biggest recurring draw, filling Manhattan’s hotels and restaurants on home-game weekends.
History
The Kansas Territorial legislature created Riley County on 30 August 1855, one of the territory’s first 33 counties, and named it for Bennet C. Riley, the general who commanded the 1829 military escort along the Santa Fe Trail and later served as California’s seventh governor. Fort Riley itself predates the county, established in 1853 to protect traffic on the Oregon and Santa Fe trails. Manhattan was founded the same year as the county, in 1855, by Free-State settlers, and took its name from stranded passengers of the steamboat company Cincinnati-Manhattan.
The county has weathered natural disaster and disease: an estimated F4 tornado struck near Irving on 30 May 1879, killing 18 people, one of the deadliest tornadoes in Kansas history. An outbreak of influenza at Fort Riley’s Camp Funston in 1918 is widely considered among the earliest documented sites of that year’s flu pandemic in the United States. Tuttle Creek Dam, completed in 1962, reshaped the county’s eastern half, flooding four towns and creating Tuttle Creek Lake.
Getting There
No interstate crosses Riley County directly; Interstate 70 runs about 9 miles south of Manhattan through neighboring Geary County, with three exits serving the city. US-24 runs through Manhattan itself, and US-77 and K-18 cross the county.
- Topeka — about 50 miles east
- Junction City — about 15 miles south
- Salina — about 60 miles southwest
- Marysville — about 40 miles north
Manhattan Regional Airport, two miles west of downtown Manhattan, offers daily American Eagle service. Kansas City’s airports are the nearest larger commercial hubs. Amtrak stopped serving Manhattan in 1971; the closest station today is in Topeka.
Frequently Asked Questions
Where is Riley County located?
It sits in the Flint Hills of north-central Kansas, about 50 miles west of Topeka, bordered by Marshall, Pottawatomie, Wabaunsee, Geary, Clay and Washington counties.
What is the population of Riley County?
71,959 at the 2020 census, with a 2025 estimate near 72,598.
How big is Riley County?
622 square miles (1,610 km2), of which 610 square miles are land.
What is the county seat of Riley County?
Manhattan, founded in 1855, is the county seat and largest city.
How many towns and cities are in Riley County?
Five incorporated cities — Manhattan, Riley, Ogden, Leonardville and Randolph — plus the Fort Riley census-designated place and seven unincorporated communities: Bala, Keats, Lasita, May Day, Walsburg, Winkler and Zeandale.
What ZIP codes does Riley County use?
66502, 66503, 66505 and 66506 for Manhattan; 66442 for Fort Riley; 66531 for Riley; 66517 for Ogden; 66449 for Leonardville; and 66554 for Randolph.
What is Riley County known for?
Kansas State University and Fort Riley, home of the Army’s 1st Infantry Division, plus Tuttle Creek Lake along its eastern border.
More counties in this state: Towns and villages in Kansas.