| ZIP Codes: | 12 ZIP Codes (12 Standard, 0 PO Box, 0 Unique) [See All] |
| Area Code: | 620 |
| Timezone: | Central (GMT -06:00) |
| Local Time: | 2:12:15 PM |
| Population: | 20,759 [See All] |
| FIPS: | 20191 |
| CBSA: | Wichita, KS |
| Land Area: | 1,195 sq mi |
| Water Area: | 3 sq mi |
| Coordinates: | 37.2745, -97.4854 |
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20,759 residents live across 12 ZIPs covering 1,195 sq mi, served by 12 distinct USPS-recognized cities.
Population moved from 22,326 to 20,759 from 2014 to 2024 — a -7.0% change. 2 ZIPs gained residents, 10 lost.
The county's wealthiest ZIP 67106 (Milton, $100,345 median) and poorest ZIP 67140 (South Haven, $47,236) are 33.4 miles apart — a 2.1× income gap across local geography.
Median home values vary 7.0× across this county — from $73,800 in 67105 (Milan) to $518,200 in 67106 (Milton).
Density varies 15× across the county — from 3 people/sq mi in 67105 (Milan) to 40 in 67152 (Wellington).
Educational attainment ranges from 11.3% bachelor's+ in 67105 (Milan) to 48.8% in 67103 (Mayfield) — the breadth of educational profiles across the area.
Within Kansas, this is the #26 most populous of 106 counties and ranks #37 for median household income .
Weighted by population, the typical household earns about $63,851 across the county — reflecting what a typical resident sees, not a simple ZIP average.
25.9% of adults age 25+ hold a bachelor's degree or higher (3,637 of 14,042 reporting).
12 Standard delivery, 0 PO Box only, 0 single-entity Unique ZIPs serve this county.
A frontier county — vast land area with only a few residents per square mile. Daily life looks very different here than in the country's denser counties.
Sumner County lost 7.0% of residents between 2014 and 2024. ZIPs that shed the largest share:
| ZIP | City | Type | Population | Median Income | Area (sq mi) | 10-yr Growth |
|---|---|---|---|---|---|---|
| 67152 | Wellington | Standard | 9,212 | $52,275 | 229.5 | -0.4% |
| 67013 | Belle Plaine | Standard | 2,678 | $69,831 | 76.6 | -2.5% |
| 67031 | Conway Springs | Standard | 2,497 | $88,000 | 117.3 | -9.7% |
| 67022 | Caldwell | Standard | 1,436 | $60,000 | 187.3 | -13.0% |
| 67119 | Oxford | Standard | 1,287 | $61,641 | 77.1 | -18.7% |
| 67140 | South Haven | Standard | 971 | $47,236 | 132.9 | 39.9% |
| 67004 | Argonia | Standard | 801 | $77,500 | 87.3 | -7.7% |
| 67120 | Peck | Standard | 575 | $96,250 | 38.9 | -65.2% |
| 67106 | Milton | Standard | 560 | $100,345 | 56.6 | 314.8% |
| 67051 | Geuda Springs | Standard | 404 | $77,663 | 76.5 | -12.7% |
| 67103 | Mayfield | Standard | 180 | $53,750 | 56.7 | -35.5% |
| 67105 | Milan | Standard | 158 | $70,625 | 58.4 | -35.8% |