Illinois · FIPS 17009 · County seat: Mount Sterling
Brown County, IL GIS & Parcel Viewer
Parcel lookups for Brown County start at Brown County Portico map (Sidwell). This page gives you that official link, notes on how the viewer works, and links to the counties next door.
Open the Brown County parcel map ↗
Opens portico.mygisonline.com in a new tab. We link out and never embed or copy parcel data.
Quick facts
| Official map | Brown County Portico map (Sidwell) |
|---|---|
| Type | County-run map |
| Website | portico.mygisonline.com |
| Access | Free, no login (checked Oct 2026) |
| County seat | Mount Sterling |
| Population | 6,294 (2023 Census Bureau estimate) |
| Land area | 306 sq mi |
| FIPS code | 17009 |
About the official source
It is a county-level map: Brown County or the company it hires keeps the parcel layer up to date. When we tested the link in October 2026 it opened with no login and no fee.
Searching for a parcel, step by step
- Press the button above. This county's viewer runs on myGISonline; 13 counties in our directory use the same service.
- Find the search option and look up a property, or zoom in on the map.
- Click a lot to see its details.
- Check the toolbar for layers, measuring and printing.
If an address search comes up empty, try the parcel number from a tax bill or deed instead, or click the lot on the map.
Brown County by the numbers
Brown County had an estimated 6,294 residents in 2023, according to the Census Bureau. With about 306 square miles of land, that works out to roughly 21 people per square mile. By population it ranks 91st of 102 counties in Illinois. Its county seat is Mount Sterling.
Nearby parcel maps
If the property sits near a county line, the parcel may belong to a neighbor. These counties border Brown County:
Maps vs. surveys
Online parcel lines are drawn for tax and planning use. They can be off by several feet, so use a recorded plat or a licensed surveyor for fences, setbacks or a sale.