Allen County is a county in Kansas, United States, along the Neosho River in the southeastern part of the state. It had a population of 12,526 at the 2020 census and covers 505 square miles (1,310 km2), of which 500 square miles are land, centred near 37°55′N 95°24′W.
Iola is the county seat, and its postal code is 66749. The county has eight incorporated cities, six unincorporated communities and twelve townships. Allen County observes Central Time and carries FIPS code 20-001.
Towns & Villages in Allen County
Allen County has 14 named places on record: 8 incorporated cities — including Iola, the seat — and 6 unincorporated communities that have no city government of their own. Two mobile-home-park listings from the old county list (“Trailside MH Park” and “Trailside MH Village”) could not be corroborated as distinct named communities and are omitted here; see notes.
| Place | Type | Township | Pop. | ZIP |
|---|---|---|---|---|
| Iola | City · seat | Iola | 5,396 | 66749 |
| Humboldt | City | Humboldt | — | 66748 |
| La Harpe | City | — | — | 66751 |
| Moran | City | — | — | 66755 |
| Gas | City | — | — | 66742 |
| Elsmore | City | Elsmore | — | 66732 |
| Savonburg | City | — | — | 66772 |
| Bassett | City | — | — | — |
| Carlyle | Unincorp. | Carlyle | — | — |
| Geneva | Unincorp. | Geneva | — | — |
| Bayard | Unincorp. | — | — | — |
| Leanna | Unincorp. | — | — | — |
| Mildred | Unincorp. | — | — | — |
| Petrolia | Unincorp. | — | — | — |
Townships
Allen County is divided into twelve townships, most named for the city or community at their centre.
| Township | Pop. (2020) | Main settlements |
|---|---|---|
| Elm | 1,259 | — |
| Marmaton | 853 | — |
| Iola | 843 | Iola |
| Elsmore | 460 | Elsmore |
| Carlyle | — | Carlyle |
| Cottage Grove | — | — |
| Deer Creek | — | — |
| Geneva | — | Geneva |
| Humboldt | — | Humboldt |
| Logan | — | — |
| Osage | — | — |
| Salem | — | — |
ZIP Codes
- 66749 — Iola (also serves Bassett and Bayard)
- 66748 — Humboldt (also serves Carlyle)
- 66751 — La Harpe
- 66755 — Moran (also serves Leanna and Mildred)
- 66732 — Elsmore (also serves Geneva)
- 66772 — Savonburg
- 66742 — Gas (a post-office-box-only ZIP; also serves Petrolia)
Every incorporated city in the county has its own ZIP code; unincorporated communities without a listed post office share the nearest town’s ZIP.
Geography
Allen County sits on gently rolling to level upland prairie in the western Osage Cuestas of southeastern Kansas. The Neosho River crosses the western part of the county, and several of its tributaries drain the rest of the county toward it. Total area is 505 square miles, of which about 500 square miles are land and roughly 5 square miles are water.
Allen County borders Anderson County to the north, Linn County to the northeast, Bourbon County to the east, Neosho County to the south, Wilson County to the southwest, Woodson County to the west and Coffey County to the northwest. Of these, only Linn County currently has a live Towns & Villages profile on this site.
Demographics
Allen County had 12,526 residents at the 2020 census, down from 13,371 in 2010; the county’s population peaked at 27,640 in 1910 during a local oil and gas boom. Iola, the seat, is the largest city with 5,396 people; Humboldt is the county’s second-largest incorporated city. That works out to a population density of roughly 25 people per square mile of land. Median household income data specific to Allen County was not independently verified for this profile; statewide, the Kansas median is $70,333.
Economy & Local Life
Agriculture on the county’s fertile prairie soils remains a core part of the local economy, alongside oil and gas production that dates back over a century. Allen County Community College, based in Iola, is the county’s largest higher-education institution and a hub of local civic life. U.S. Routes 54, 59 and 169 carry most of the county’s through traffic and commerce.
History
Allen County was organized on August 25, 1855, and named for William Allen, a United States senator from Ohio. The Richard J. Fuqua family are recorded as the first white settlers, arriving in January 1855. The county’s population rose sharply in the early twentieth century on the strength of oil and gas discoveries near Iola before declining through most of the century that followed.
Getting There
Allen County is reached by U.S. Routes 54, 59 and 169, which converge near Iola.
- Chanute, Kansas — about 15 miles south, via US-169
- Fort Scott, Kansas — about 30 miles east, via US-54
- Emporia, Kansas — about 45 miles northwest, via US-54
- Wichita, Kansas — about 95 miles west
The nearest commercial airport is Wichita Dwight D. Eisenhower National Airport.
Frequently Asked Questions
Where is Allen County, Kansas?
It is in the southeastern part of Kansas, along the Neosho River, about 95 miles east of Wichita.
What is the population of Allen County?
12,526 people, at the 2020 census.
How big is Allen County?
505 square miles (1,310 km2), of which about 500 square miles are land.
What is the county seat of Allen County?
Iola is the county seat.
How many towns are in Allen County?
Eight incorporated cities and six unincorporated communities.
What ZIP codes are in Allen County?
66749 (Iola), 66748 (Humboldt), 66751 (La Harpe), 66755 (Moran), 66732 (Elsmore), 66772 (Savonburg) and 66742 (Gas).
Why is the county named Allen?
It honors William Allen, a U.S. senator from Ohio, at its organization in 1855.
More counties in this state: Towns and villages in Kansas.