Blog · October 14, 2026 · Illinois
Jefferson County Plat Book: finding and using one
If the land is near Camp Ground, plat books show ownership by township; the parcel viewer shows it today.
Main page: Jefferson County, IL GIS & Parcel Viewer (official map link, county facts and neighboring maps).
Platbookmapper is an Amazon Associate. If you buy through an Amazon link on this page, we earn a commission. The link is a product, not the county map.
Want a copy of the Jefferson County plat book? It's a printed atlas of landownership, usually by township, useful for farms near Opdyke. Covered here for this county: what's in a plat book, where to look for printed copies, and the free online map that stays current, at least around Mount Vernon.
Tracking down a Jefferson County plat book
For acreage around Belle Rive, plat books are commercial atlases, that map ownership across the countryside, often organized by township.
The free map to start with
Go first to the Sidwell Portico - Jefferson County Assessor; it maps each tax parcel around Belle Rive and Boyd. Without an address in hand, follow Interstate 57 on the aerial and click the parcel itself. If the land is near Belle Rive, the parcel card usually lists the owner of record, assessed acreage, the parcel number and often a sale date.
On site with the map
Most viewers work in a phone browser, useful out on a road near Boyd, but coverage can be spotty out of town. A printout of the tract near Belle Rive is a good backup.
Who uses plat books
Farmers, hunters and appraisers near Camp Ground use plat books for a big-picture view of who owns what.
Jefferson County in a few facts
Mount Vernon holds the county offices, where most land records are kept. Other places on the map include Nason, Belle Rive, Bluford, and Bonnie, each with its own cluster of lots. Roughly 36,320 people live in Jefferson County (Census estimate, 2023) spread over roughly 571 square miles. The county was formed in 1819, and some chains of title near Boyd are long.
Land on the county line
The county touches Franklin County, Hamilton County, Marion County, Perry County, and Washington County; every one of them runs a separate parcel map, especially near Camp Ground. Acreage along the edge near Mount Vernon may show up in two county records, so look at the neighboring map as well. With a lot near Opdyke, our state page lists every neighboring county map for Illinois.
Editions and availability
Older editions near Camp Ground turn up in libraries and historical societies, useful for family or title research.
Making your own township pages
Screenshot each section of the viewer around Bluford to build your own up-to-date atlas.
Backing up the map with records
On ground around Bluford, the map is an index, not the title: deeds, subdivision plats and easements for parcels in the county are kept by the county Recorder of Deeds (in many counties the County Clerk and Recorder). Long-held tracts near Belle Rive can go back through many deeds, so a title company earns its fee on a real sale.
Getting answers from the right desk
For assessment questions about property around Mount Vernon belong with the Supervisor of Assessments, working with township assessors, which maintains the tax roll. Zoning, permits and septic questions near Mount Vernon need the planning or permitting office, depending on whether the land is inside town limits.
Reading the legal description
Illinois uses the Public Land Survey System, so deeds around Mount Vernon reference sections and townships. Each section is nominally a mile square, about 640 acres, and a township holds 36 of them, though real sections near Belle Rive vary in size. Write down the legal description for the tract near Dareville before you request a deed or survey.
A word on accuracy
Tax maps are drawn for assessment, not surveyed, so a tree line near Bluford can sit several feet off the line on screen. On ground around Mount Vernon, records update in batches, so a deed recorded last month might lag behind.
Between editions
For current names, use the Sidwell Portico - Jefferson County Assessor, across the county.
Two kinds of plat
A plat book is not a recorded plat: recorded plats near Dareville are filed with the county Recorder of Deeds (in many counties the County Clerk and Recorder), and the atlas is just a guide.
Frequently asked
Is a plat book legal proof in Jefferson County?
For land near Belle Rive, a survey sets boundaries, not an atlas.
How accurate are plat book acreages around Bonnie?
With a lot near Camp Ground, the deed and a survey decide.
Who sells plat books around Bluford?
The extension office or courthouse near Dareville usually knows.
How do I research old landowners near Ina?
In and around Bakerville, some older atlases have been digitized.
How do I save a parcel from the viewer in Jefferson County?
Out toward Camp Ground, some viewers offer PDF export; downloads of raw data vary by county.
Open the official Jefferson County, IL parcel map See it in the Platbookmapper directory
Not a survey. County GIS and tax parcel maps are assessment and planning layers. They are not a substitute for a recorded plat, deed, or licensed survey, especially for fences, setbacks, or boundary disputes.