At a glance
Use it to identify the parcel, tax record, lot shape, and neighbors.
GIS and assessment lines are research tools, not certified boundary locations.
Fence, corner marking, sale, neighbor issue, permit, or setback decision.
Common starting range for residential property-line work.
Start with the free research
The point of free research is not to become your own surveyor. It is to collect the right records, avoid vague calls, and help a surveyor understand the job quickly.
Search the county GIS, assessor, or supervisor of assessments record. Save the parcel number, owner or tax record, legal description, lot and block if shown, acreage, and map link.
Pull deeds, subdivision plats, easements, right-of-way documents, and other recorded instruments from the county recorder or clerk record system.
Search for a prior survey, mortgage survey, title commitment, settlement packet, builder site plan, permit drawing, or old map reference.
Take photos of iron pins, pipes, stakes, fence corners, walls, driveways, creek banks, tree lines, road edges, and any neighbor concern.
What maps can and cannot tell you
| Item | Useful for | Do not use it for |
|---|---|---|
| County GIS or tax map | Parcel ID, owner or tax record, approximate lot shape, neighboring parcels, acreage, and local record links. | Setting a fence, resolving a dispute, or treating the map line as a surveyed boundary. |
| Recorder, clerk, or plat record | Deeds, subdivision plats, easements, survey or monument records where available, and transfer documents. | Replacing a surveyor's research and field evidence reconciliation. |
| Deed or legal description | Understanding how the property is described and what records a surveyor must research. | Measuring the line yourself without reconciling monuments, plats, adjoining deeds, and field evidence. |
| Recorded subdivision plat or filed map | Lot number, block, dimensions, easements, rights of way, and intended subdivision layout. | Assuming every old marker remains undisturbed or that later occupation matches the map. |
| Prior survey | Existing corners, measurements, encroachments, easements, notes, and possible update path. | Relying on it blindly if the scope was limited, the property changed, or the survey is old. |
Illinois county GIS maps are helpful for research, but they are not a substitute for a Professional Land Surveyor locating the boundary from records and field evidence. Some counties also warn that plats of survey are not always filed with the recorder, so your own closing file may be important.
Why Illinois property-line searches get messy
Illinois records are county-based
Assessor, GIS, recorder, clerk, and plat records vary by county. Cook County, collar counties, downstate counties, and rural counties often have different search workflows.
PLSS and subdivision records both matter
Some properties turn on section, township, and range evidence. Others turn on subdivision plats, lot and block descriptions, easements, and old surveys.
Plats of survey may not be easy to find
A prior survey may be in your closing packet, lender file, builder records, or with a prior owner rather than the recorder office.
Dense suburbs and older city lots can be tight
Cook, DuPage, Will, Kane, Lake, and older city lots can involve fences, alleys, garages, party walls, easements, and improvements close to the line.
When you need a licensed surveyor
The simplest test is risk. If being wrong by a foot would cost money, create conflict, delay a permit, or affect a closing, do not rely on the map.
Fence, wall, or landscaping near the line
- Ask for
- Boundary survey with corners marked, line staking, or both.
- Send first
- Fence plan, parcel ID, prior survey, photos, and where the work will go.
- Watch for
- Setbacks, easements, utilities, roads, drainage, and neighbor concerns.
Neighbor disagreement
- Ask for
- Boundary survey with the disputed line and relevant evidence shown clearly.
- Send first
- Photos, neighbor notes, old surveys, deed, fence history, and any letters you received.
- Watch for
- A surveyor can locate boundary evidence. They are not your attorney or mediator.
Buying land or a house
- Ask for
- Property survey, boundary survey, or survey update depending on what already exists.
- Send first
- Address, county, parcel ID, listing, title request, old survey, and closing timeline.
- Watch for
- Access, easements, old fences, acreage mismatch, missing corners, and title exceptions.
Addition, driveway, pool, or setback
- Ask for
- Boundary survey, setback information, and possibly topographic support for design.
- Send first
- Permit comments, builder notes, site plan, and proposed improvement location.
- Watch for
- Setbacks and easements can matter as much as the property line itself.
What local supply says about getting help
Find Land Surveyor currently lists 275 Illinois surveying firm or office profiles across 58 counties. Visible supply is densest around Cook, Will, DuPage, Kane, Peoria, Lake, Winnebago, Sangamon, McHenry, Madison, La Salle, Macon, Johnson, Champaign, Effingham, Rock Island, McLean, Williamson, Coles, Kendall, and Tazewell.
Chicago-area counties generally have several firms, while downstate, rural, and acreage parcels may be better handled by a regional firm that regularly works with local recorder records, section evidence, and field conditions.
Links to check first
Use Illinois license lookup to verify a Professional Land Surveyor or design firm.
IDFPR guidance on Illinois Professional Land Surveyor licensing and practice.
Useful explanation of GIS maps, parcel lines, and plats of survey in a county context.
Example of county land records, subdivision plats, surveys, and monument records.
Copy and paste this to a surveyor
Use this when you want a clear estimate for property-line work.
How to avoid expensive mistakes
- Do not build from a map screenshot: use assessment and GIS maps to orient yourself, not to set a fence or resolve a line.
- Ask for the right deliverable: corners marked, full line staking, signed plan, and topo support are different scopes.
- Send documents early: deed, plat, prior survey, parcel ID, title request, and photos can speed up evaluation.
- Say why you need it: fence, neighbor issue, closing, addition, rural parcel, permit, or setback need changes the work.
- Verify the responsible surveyor: check Illinois licensing and ask who signs and seals the deliverable.
- Keep legal questions separate: a survey can locate boundary evidence. Ownership rights, adverse possession, easements, and disputes may also need an attorney.