When was Richland County founded?

Richland County was founded in 1841, formed from Clay County and Lawrence County, and named after Richland County, Ohio.

What is the county seat of Richland County?

The county seat of Richland County is Olney.

Is there an online parcel map for Richland County?

Not that we have found yet. Lot lines and owners of record are kept by the county assessor's office. When a public parcel map appears, it shows here.

Has Richland County's boundary or name changed?

Richland County was created in 1841 from Clay County and Lawrence County. The Atlas of Historical County Boundaries records no boundary change since.

Is my lot in a flood zone?

We do not have flood maps for Richland County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

County · code 17159

Richland CountyIllinois

Richland County is a county in Illinois with its seat in Olney. It was formed on June 7, 1841.

Founded1841
County seatOlney
Named forRichland County, Ohio
Land area360 sq mi + 1.9 sq mi water
Population15,813 2020 Census

Open the free map Click any parcel in Richland County: acreage, parcel id, address and who publishes the map. No sign-in.

Updated 19 October 2026

Census outline · seat marked

History

Formed in 1841 from Clay County and Lawrence County

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

Richland County was created from Clay and Lawrence counties on June 7, 1841.

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

1841
Richland County created Richland created from Clay and Lawrence.
from Clay from Lawrence
7 June 1841 · Ill. Laws 1840-1841, pp. 77-79

Land and parcels

What the maps cover in Richland

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

Parcels Missing

No public parcel map found for Richland County yet. Lot lines and owners of record are kept by the county assessor's office.
Address points Missing

No public address points layer found for Richland County yet.
Buildings Reference

Roof outlines traced from aerial imagery from FEMA Response Geospatial Office with Oak Ridge National Laboratory (ORNL). Good for seeing what is on a lot; not accurate enough to set a fence from.
checked 18 October 2026

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

Richland by the Census

Population

15,813 2020 Census count

Housing units

7,364 2020 Census count

Land area

360 square miles

Water area

1.9 square miles

People per sq mi

44 population ÷ land area

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

See your own lot on these maps

Open Richland 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.

Open the free map no sign-in Pro early access

Questions

Common questions about Richland County

When was Richland County founded?: Richland County was founded in 1841, formed from Clay County and Lawrence County, and named after Richland County, Ohio.
What is the county seat of Richland County?: The county seat of Richland County is Olney.
Is there an online parcel map for Richland County?: Not that we have found yet. Lot lines and owners of record are kept by the county assessor's office. When a public parcel map appears, it shows here.
Has Richland County's boundary or name changed?: Richland County was created in 1841 from Clay County and Lawrence County. The Atlas of Historical County Boundaries records no boundary change since.
Is my lot in a flood zone?: We do not have flood maps for Richland County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.

Nearby