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County · code 19119

Lyon CountyIowa

Lyon County is a county in Iowa, with its county seat in Rock Rapids. It was formed in 1851.

  • Founded1851
  • County seatRock Rapids
  • Named forNathaniel Lyon
  • Land area588 sq mi + 0.2 sq mi water
  • Population11,934 2020 Census
  • Parcels mapped11,868 checked 14 October 2026
Open the free map Click any parcel in Lyon County: acreage, parcel id, address and who publishes the map. No sign-in.

Updated

Rock, MNSiouxLincoln, SDOsceolaO'Brien Rock Rapids Census outline · seat marked

Where it is

Lyon on the map of Iowa

Iowa has 99 counties and county equivalents, each with its own records office. Shapes with a page are links.

Adair CountyAdams CountyAllamakee CountyAppanoose CountyAudubon CountyBenton CountyBlack Hawk CountyBoone CountyBremer CountyBuchanan CountyBuena Vista CountyButler CountyCalhoun CountyCarroll CountyCass CountyCedar CountyCerro Gordo CountyCherokee CountyChickasaw CountyClarke CountyClay CountyClayton CountyClinton CountyCrawford CountyDallas CountyDavis CountyDecatur CountyDelaware CountyDes Moines CountyDickinson CountyDubuque CountyEmmet CountyFayette CountyFloyd CountyFranklin CountyFremont CountyGreene CountyGrundy CountyGuthrie CountyHamilton CountyHancock CountyHardin CountyHarrison CountyHenry CountyHoward CountyHumboldt CountyIda CountyIowa CountyJackson CountyJasper CountyJefferson CountyJohnson CountyJones CountyKeokuk CountyKossuth CountyLee CountyLinn CountyLouisa CountyLucas CountyMadison CountyMahaska CountyMarion CountyMarshall CountyMills CountyMitchell CountyMonona CountyMonroe CountyMontgomery CountyMuscatine CountyO'Brien CountyOsceola CountyPage CountyPalo Alto CountyPlymouth CountyPocahontas CountyPolk CountyPottawattamie CountyPoweshiek CountyRinggold CountySac CountyScott CountyShelby CountySioux CountyStory CountyTama CountyTaylor CountyUnion CountyVan Buren CountyWapello CountyWarren CountyWashington CountyWayne CountyWebster CountyWinnebago CountyWinneshiek CountyWoodbury CountyWorth CountyWright CountyLyon County Lyon
Counties of Iowa · Lyon highlighted

History

Formed in 1851 from Polk County

An old deed may name a county that no longer exists, or a boundary that has since moved.

Originally created as Buncombe County in 1851 from Polk County, it was not fully organized at first and was attached to Woodbury County for revenue, election, and judicial purposes in 1853. Buncombe County was renamed Lyon in 1862, named after Nathaniel Lyon, and became fully organized and detached from Woodbury County in 1872.

Boundary changes from the Newberry Library, Atlas of Historical County Boundaries.

  1. 1851
    Lyon County created Buncombe (now Lyon) created from Non-County Area 9 attached to Polk; Buncombe not fully organized, not attached.
    from Polk
    · Iowa Acts 1850-1851, ch. 9, sec. 50/p. 38
  2. 1853
    Changed Buncombe (now Lyon) attached to Woodbury "for revenue, election, and judicial purposes".
    Woodbury
    · Iowa Acts 1852-1853, ch. 8, sec. 14/p. 24
  3. 1862
    Renamed Buncombe renamed Lyon.
    formerly Buncombe
    · Iowa Acts 1862, ext. sess., ch. 23, sec. 1/p. 22
  4. 1872
    Changed Lyon fully organized, detached from Woodbury.
    Woodbury
    · Swisher, "Organization of Counties," 575

Land and parcels

What the maps cover in Lyon

Who publishes each layer, how good it is, and when we last checked.

Official
from the office that keeps the record
Good enough
a reliable statewide or national copy
Fallback
a guide only; check the official record
Missing
nothing public found yet

People and land

Lyon by the Census

Population
11,934 2020 Census count
Housing units
4,817 2020 Census count
Land area
588 square miles
Water area
0.2 square miles
People per sq mi
20 population ÷ land area

Source: US Census Bureau, 2020 Census; US Census Bureau, 2020 Gazetteer Files. Not endorsed or certified by the Census Bureau.

Rules and offices

Lyon County's official site

We have found the county's site but not its offices yet; start there.

County government

See your own lot on these maps

Open Lyon County on Parcel Chart's free map and click your parcel. Save it with a free account; the full record of your place (site map, projects, documents) is Pro, in early access.

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Questions

Common questions about Lyon County

When was Lyon County founded?
Lyon County was founded in 1851, formed from Polk County, and named after Nathaniel Lyon.
What is the county seat of Lyon County?
The county seat of Lyon County is Rock Rapids.
Is there an online parcel map for Lyon County?
Yes. A public source publishes a parcel map of 11,868 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
Has Lyon County's boundary or name changed?
Lyon County was created in 1851 from Polk County. Since then the Atlas of Historical County Boundaries records 3 later changes, chiefly involving Woodbury County and Buncombe County. It was formerly called Buncombe.
Is my lot in a flood zone?
We do not have flood maps for Lyon County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Nearby

Counties next door