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Williamson County, IL Parcels & GIS Data

Williamson County, IL parcel data: 51,108 property records with owner names, assessed values, land use, acreage, and addresses. Preview and download.

Land Records publishes Williamson County, Illinois parcel data covering 51,108 property records.

This page documents parcel-level coverage for Williamson County, Illinois. Each parcel record carries its boundary polygon (GIS geometry) along with attributes such as the parcel ID/APN, owner name and mailing address, situs (property) address, assessed land and improvement values, acreage, land-use and zoning codes, year built, and most recent sale price and date. Exact fill rates for Williamson County are listed in the attribute-coverage table below. Preview the data in the interactive explorer, or download the complete Williamson County property dataset.

Williamson County is a county in Illinois and is part of the Metro Lakeland area of Southern Illinois. Its largest city and county seat is Marion. As of the 2020 census, it had a population of 67,153.

FIPS 17199

Official county website: http://www.williamsoncountyil.gov/

The FIPS code for Williamson County is 17199.

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Attribute coverage

Williamson County contains 51,108 parcels in the current dataset. Column coverage is the percentage of those parcels for which the attribute is populated (non-NULL). For the LBCS columns, only real classifications count: the to-be-determined and not-applicable placeholder codes are excluded.

ColumnCoverageRecords populated
lrid100%51,108
parcelid100%51,104
parcelid285.0%43,450
ogparcelid100%51,104
ogparcelid20.5%275
parentid<0.1%0
stackid<0.1%0
geoid100%51,108
statefp100%51,108
countyfp100%51,108
countyname100%51,108
cousubfp100%51,108
cousubname100%51,108
tractce100%51,108
tractname100%51,108
taxacctnum<0.1%0
taxyear100%51,108
taxdistrict<0.1%0
usecode0.1%29
usedesc84.0%42,925
zoningcode<0.1%0
zoningdesc<0.1%0
numbldgs55.3%28,260
numunits53.7%27,429
yearbuilt<0.1%0
numfloors35.2%17,977
bldgsqft<0.1%0
bedrooms<0.1%0
halfbaths<0.1%0
fullbaths<0.1%0
imprvalue99.0%50,575
landvalue99.0%50,575
agvalue99.0%50,575
totalvalue99.8%51,001
taxacres1.6%829
calcarea100%51,108
saleamt83.9%42,869
saledate70.0%35,792
ownertype97.3%49,726
ownername97.3%49,726
owneraddr83.9%42,869
ownercity<0.1%0
ownerstate<0.1%0
ownerzip<0.1%0
parceladdr99.4%50,807
parcelcity0.5%262
parcelstate100%51,108
parcelzip100%51,108
legaldesc83.5%42,673
township100%51,107
section100%51,107
qtrsection100%51,107
range100%51,107
plssdesc100%51,107
book71.8%36,686
page71.8%36,687
block29.6%15,104
lot52.9%27,052
parceltype1.2%591
accesstype10.8%5,500
iucnclass10.0%5,121
placename14.0%7,159
placetype13.9%7,118
firmid100%51,108
firmdate100%51,108
fldzone100%51,108
zonesubty96.6%49,383
staticbfe<0.1%5
elevmin99.2%50,702
elevmax99.2%50,702
elevavg99.2%50,702
fireplaces<0.1%0
heating<0.1%0
heatfuel<0.1%0
cooling<0.1%0
foundation<0.1%0
roofcover<0.1%0
siding<0.1%0
bldgtype<0.1%0
naicscode17.5%8,956
frsid<0.1%1
dfrurl<0.1%1
caapermit<0.1%1
cwapermit<0.1%1
rcrapermit<0.1%1
updated85.0%43,454
centroidx100%51,108
centroidy100%51,108
surfpointx100%51,108
surfpointy100%51,108
geom100%51,108
extras100%51,108
ownerlist71.2%36,405
placefp58.1%29,702
zoningurl<0.1%0
lbcsactivity82.6%42,238
lbcsfunction82.6%42,230
lbcstype79.8%40,772
lbcscharacter99.3%50,737
lbcsownership97.6%49,894
sourceurl<0.1%0

Schema mapping

How source columns from the acquired Williamson County GIS layers map into the harmonized entity schemas and assemble into the published parcel table, alongside supplemented fields (elevation, flood zone) and deterministic columns.

Schema mapping — Williamson County, Illinois (17199) 1 entity · most recent acquisition per entity · generated 2026-10-10 direct column transformed (expression) geometry extras json supplemented determined ALL ENTITIES → FINAL PARCEL SCHEMA Harmonized entity columns assemble into publish.parcel_layer — matched by column name. Supplemented fields show their fill rate in this county. SOURCE COLUMNS HARMONIZED ENTITIES PUBLISH.PARCEL_LAYER PARCEL parcelid parcelid2 totalvalue taxacres ownername parceladdr geom parentid 2 cols ⇢ parcelid parcelid2 totalvalue taxacres ownername parceladdr geom parentid extras determined · ground truth 100% lrid 100% geoid 100% statefp 100% countyfp 100% countyname 100% cousubfp 100% cousubname 100% tractce 100% tractname 100% taxyear 85.0% updated geom · derived from geometry geom dem.us_1m · USGS 1m DEM 99.2% elevmin 99.2% elevmax 99.2% elevavg s_fld_haz_ar · FEMA NFHL 100% fldzone 96.6% zonesubty 0.0% staticbfe 100% firmdate 100% firmid supplemented · derived / other pipelines 84.0% usedesc 55.3% numbldgs 53.7% numunits 99.0% imprvalue 99.0% landvalue 99.0% agvalue 83.9% saleamt 70.0% saledate 83.9% owneraddr 100% parcelstate 100% parcelzip 83.5% legaldesc 100% township 100% section 100% qtrsection 100% range 100% plssdesc 71.8% book 71.8% page 52.9% lot 71.2% ownerlist 58.1% placefp 82.6% lbcsactivity 82.6% lbcsfunction 79.8% lbcstype 99.3% lbcscharacter 97.6% lbcsownership lrid parcelid parcelid2 ogparcelid ogparcelid2 parentid geoid statefp countyfp countyname cousubfp cousubname tractce tractname taxyear usedesc numbldgs numunits imprvalue landvalue agvalue totalvalue taxacres calcarea saleamt saledate ownertype ownername owneraddr parceladdr parcelstate parcelzip legaldesc township section qtrsection range plssdesc book page lot firmid firmdate fldzone zonesubty staticbfe elevmin elevmax elevavg updated centroidx centroidy surfpointx surfpointy geom extras ownerlist placefp lbcsactivity lbcsfunction lbcstype lbcscharacter lbcsownership publish.parcel_layer columns not fed by these sources (38) — empty or below 50% fill in this county stackid, taxacctnum, taxdistrict, usecode, zoningcode, zoningdesc, yearbuilt, numfloors, bldgsqft, bedrooms, halfbaths, fullbaths, ownercity ownerstate, ownerzip, parcelcity, block, parceltype, accesstype, iucnclass, placename, placetype, fireplaces, heating, heatfuel, cooling foundation, roofcover, siding, bldgtype, naicscode, frsid, dfrurl, caapermit, cwapermit, rcrapermit, zoningurl, sourceurl PARCEL 8 mapped · 7 transformed · 2 kept in extras · 46 unmapped (NULL) SOURCE COLUMNS HARMONIZED → PARCEL parcelid parcelid2 totalvalue taxacres ownername parceladdr geom parentid parcelid NULLIF(TRIM(parcelid), '')::text parcelid2 NULLIF(TRIM(parcelid2), '')::text totalvalue NULLIF(TRIM(totalvalue), '')::text taxacres NULLIF(TRIM(taxacres), '')::text ownername NULLIF(TRIM(ownername), '')::text parceladdr NULLIF(TRIM(parceladdr), '')::text geom parentid NULLIF(TRIM(parentid), '')::text extras · 2 source columns preserved as json ogparcelid, geoid extras not present in source — filled with NULL (46) taxacctnum, taxyear, usecode, usedesc, zoningcode, zoningdesc, numbldgs, numunits, yearbuilt, numfloors, bldgsqft, bedrooms, halfbaths fullbaths, imprvalue, landvalue, agvalue, saleamt, saledate, owneraddr, ownercity, ownerstate, ownerzip, parcelcity, parcelstate, parcelzip legaldesc, township, section, qtrsection, range, plssdesc, book, page, block, lot, updated, sourceurl, taxdistrict, heatfuel, fireplaces heating, cooling, foundation, roofcover, siding

Neighboring counties

Parcel data for counties bordering Williamson County:

Frequently asked questions

Where can I find Williamson County, IL parcel and GIS data?

Land Records publishes a Williamson County, IL parcel dataset in which every parcel carries its boundary polygon (GIS geometry) along with ownership, assessed value, land use, acreage, and sale history. Preview it in the interactive explorer on this page, or download the full Williamson County, IL dataset as a GeoPackage or CSV.

How many parcels are in Williamson County, IL?

The current dataset contains 51,108 parcel records for Williamson County, IL, each with its boundary geometry and assessor attributes.

What is the FIPS code for Williamson County, IL?

The FIPS code for Williamson County, IL is 17199.

What information does each Williamson County, IL parcel record include?

Each Williamson County, IL parcel record includes the parcel ID/APN, owner name and mailing address, situs (property) address, assessed land and improvement values, acreage, land-use and zoning codes, year built, and the most recent sale price and date — plus the parcel boundary polygon. Per-attribute fill rates are listed in the coverage table on this page.

Is Williamson County, IL parcel data free?

You can preview Williamson County, IL parcels for free in the interactive explorer. The complete dataset is available as a one-time download or through the nationwide parcel web service; see the download options on this page for current pricing.

Does Williamson County, IL have an official GIS or property records website?

Yes — the official Williamson County, IL government website is linked in the county details above. Land Records standardizes Williamson County, IL assessor and recorder records into a single nationwide parcel schema with GIS boundary geometry.

On this page

Attribute coverageSchema mappingNeighboring countiesFAQRelated