Allen County, KS zoning map, flood zone and property lines by address
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Towns in Allen County: Iola, Humboldt.
Flood zone by address
ParcelSheet reads FEMA's National Flood Hazard Layer at the lot: the zone, whether it is a high risk area where lenders ask for flood insurance, and the base flood elevation where FEMA lists one. FEMA's countywide study for Allen County has 29 FIRM panels, the newest effective July 2011; no coastal V zones are mapped in it.
The official panel and any Letter of Map Amendment are at FEMA's Map Service Center. An elevation certificate for an Allen house comes from a licensed surveyor and is often on file with the county or city building office.
Property lines
The parcel outline, parcel number and mapped size come from the Kansas county parcel layers (each county publishes its own), so an Allen lot shows the same lines the county appraiser draws. Allen County covers about 320,190 acres of land and 3,218 acres of water.
Mapped lines are approximate. The Allen County appraiser keeps the parcel record (Allen County website); a licensed surveyor sets the true corners.
Zoning
Allen County zones its unincorporated land, and Iola, Humboldt each zone the land inside their limits. ParcelSheet shows the use the county appraiser lists for the lot and links the county planning and zoning office for the district, the uses it allows and the lot size it needs.
ADU and guest houses
Under Kansas's planning and zoning law for cities and counties (Kansas Statutes 12-741 and following), local governments can allow an accessory dwelling unit on a lot with a house. Whether an Allen lot can add one depends on its district; the county planning and zoning office has the rule. ParcelSheet shows the mapped lot size and the ground's slope, the first two things the question turns on.
Septic and soil
ParcelSheet reads the USDA soil survey at the lot: the soil's name, its septic absorption rating and whether it is prime farmland. Allen County is soil survey area KS001, Allen County, Kansas, last updated August 2026, on Web Soil Survey.
A new or changed septic system in Allen County needs a permit from the Allen County sanitarian (under the county sanitary code and Kansas Department of Health and Environment standards).
Setbacks
Setbacks in Allen County come from the zoning district: the front, side and rear distances a house must keep. ParcelSheet does not draw setback lines; the county zoning office gives them for the lot's district, and Iola and Humboldt for land inside their limits.
Hazards that apply
- Wetlands and wildfire. ParcelSheet shows the National Wetlands Inventory near an Allen lot and the Forest Service wildfire hazard rating at it.
Questions
Is my house in a flood zone in Allen County?
Type the address in the box above and ParcelSheet reads FEMA's flood zone at the lot's center. FEMA's countywide flood map for Allen County has 29 panels, the newest effective July 2011. A lender or insurer uses the official FIRM panel; FEMA's Map Service Center has it.
How do I find property lines in Allen County?
Open the Kansas map, type the address, and the parcel outline from the Allen County appraiser shows on the map with its parcel number and mapped size. Mapped lines are approximate; only a licensed surveyor sets the true corners.
What is my property zoned in Allen County?
Zoning in Allen County is set by the county for unincorporated land and by each city (such as Iola, Humboldt) inside its own limits. ParcelSheet shows the use code the county appraiser lists and links the office that sets the zoning; the planning office has the final word.
Can I build an ADU in Allen County?
Under Kansas's planning and zoning law for cities and counties (Kansas Statutes 12-741 and following), counties and cities can allow an accessory dwelling unit, and each sets its own rules. In Allen County ask the zoning office for the lot's district first; ParcelSheet shows the lot size as mapped so you can see the room you have.
Do I need a septic permit in Allen County?
Yes. A new or changed septic system in Allen County needs a permit from the Allen County sanitarian (under the county sanitary code and Kansas Department of Health and Environment standards). ParcelSheet shows the USDA soil survey's septic rating at the lot, from survey area KS001 (Allen County, Kansas).
What can I build on 5 acres in Allen County?
Zoning in Allen County is set by the county for unincorporated land and each city inside its own limits (such as Iola, Humboldt). The zoning district decides the uses, how many homes and the smallest lot it allows on 5 acres. ParcelSheet shows the lot size as mapped and the use code on the parcel record; the planning office has the district and its rules. See the Allen County website.
What are the residential setbacks in Allen County (2026)?
Setbacks in Allen County come from the zoning code of the county, or of the city when the lot is inside city limits: the front, side and rear distances depend on the lot's district. ParcelSheet does not draw setback lines or give a number it did not read; the zoning office gives them for the district. See the Allen County website.
Next to Allen County: Anderson County, Bourbon County, Neosho County, Woodson County.
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