Illinois Survey Guide

Land Surveying in Illinois: What Property Owners Need to Know

Updated for 2026 · 7 min read · How-To Guides

Key takeaway

Illinois land surveying laws explained for property owners. PLS licensing, plat requirements, fence rules, and boundary rights in plain language.

Illinois Land Surveying Laws: A Guide for Property Owners

Illinois property owners deal with surveys in many situations: buying or selling a home, building a fence, subdividing a parcel, or resolving a boundary dispute. Understanding the laws that govern land surveying in Illinois helps you know your rights, avoid expensive mistakes, and work effectively with licensed surveyors. This guide covers the key laws every Illinois property owner should know.

The Illinois Professional Land Surveyor Act of 1989

The Illinois Professional Land Surveyor Act of 1989 (225 ILCS 330/) is the foundation of land surveying regulation in the state. It defines who can legally perform land surveys, establishes the licensing process, and sets standards for professional conduct.

Key provisions property owners should know:

  • Only a licensed Professional Land Surveyor (PLS) may establish or re-establish property boundaries, set monuments, or prepare plats in Illinois
  • The Illinois Department of Financial and Professional Regulation (IDFPR) licenses and regulates all Illinois PLSs
  • Surveyors must pass education requirements, gain supervised experience, and pass a national and state examination to earn an Illinois PLS license
  • Disciplinary actions against licensed surveyors are handled by IDFPR and are publicly viewable at idfpr.illinois.gov

The practical implication for property owners: if someone tells you they surveyed your property but they are not a licensed Illinois PLS, that work has no legal standing. Always verify a surveyor's license before hiring.

The Illinois Plat Act

The Illinois Plat Act (765 ILCS 205/) governs the platting and recording of subdivided land. If you want to divide your property into two or more parcels for sale or development, this law applies to you.

Key requirements under the Plat Act:

  • A plat of subdivision must be prepared by a licensed Illinois PLS
  • The plat must meet specific technical requirements for dimensions, bearings, and monument descriptions
  • The plat must be certified by the PLS with their seal and signature
  • The plat must be reviewed and approved by the county or municipality before it can be recorded
  • Until a plat is recorded with the county recorder, lots described within it generally cannot be legally conveyed

Subdivision platting is most commonly needed when landowners in rural counties want to split a farm parcel, or when developers create new residential subdivisions in rapidly growing collar counties around Chicago.

The Illinois Fence Act

The Illinois Fence Act (765 ILCS 130/) governs shared fences between adjacent rural property owners. This law applies to agricultural and rural properties outside incorporated municipalities.

Key provisions:

  • Adjacent rural landowners are generally required to share equally in the cost of building and maintaining a division fence between their properties
  • Disputes between neighbors about fence costs or location are handled through a process involving township fence viewers
  • The Fence Act does not define where the boundary is. If neighbors disagree about where the property line falls, a PLS survey is the legal method for resolving that question
  • The Fence Act does not apply within most incorporated municipalities, where local ordinances govern fence placement and setbacks

If you are a rural Illinois property owner building a division fence, coordinate with your neighbor before construction begins. If there is any question about where the boundary falls, get a survey first.

Local Ordinances and Setback Requirements

Beyond state law, Illinois municipalities and counties often have local ordinances that affect land surveys. Common local requirements include:

  • Setback confirmations before issuing building or fence permits
  • Survey certificates required for certain construction permits
  • Subdivision approval processes that require county or municipal plat review
  • Floodplain ordinances that require elevation certificates for construction in flood zones

Check with your local municipality or county planning department before starting any construction project that might be near a property line, setback zone, or flood hazard area.

Boundary Disputes and Legal Resolution in Illinois

When neighbors disagree about where a property line is, the legal process in Illinois follows a clear path:

Step 1: Hire a Licensed PLS

The first step in any boundary dispute is to hire a licensed Illinois PLS to perform a boundary survey. The PLS will research recorded deeds, plats, and field evidence to establish the boundary's legal location. The result is a survey plat that documents the boundary with legal precision.

Step 2: Attempt Negotiation

If both parties accept the survey findings, a boundary line agreement can be recorded with the county recorder to resolve the dispute permanently. This is the least expensive path to resolution.

Step 3: Legal Action

If neighbors cannot agree, the dispute may require litigation. Illinois courts generally treat a licensed PLS survey as authoritative evidence of boundary location. Some surveyors in Illinois offer expert witness services and can testify to the legal basis for their boundary findings.

Adverse Possession in Illinois

Illinois law allows a person to claim ownership of land they have continuously occupied under adverse possession, but the requirements are strict. Under Illinois law, adverse possession requires 20 years of open, hostile, actual, exclusive, and continuous possession. This is a high bar, and the claim must be litigated in court. A survey is typically required to document the extent of any claimed adverse possession area.

Flood Zone Regulations

Properties in FEMA Special Flood Hazard Areas along the Illinois River, Rock River, Kaskaskia, and Wabash River corridors are subject to federal floodplain regulations and local floodplain ordinances. Illinois has adopted a statewide floodplain management program administered by the Illinois Emergency Management Agency (IEMA) in coordination with FEMA. If you build in a flood zone, your local ordinance likely requires an elevation certificate from a licensed PLS before a certificate of occupancy is issued.

Property Owner Rights During a Survey

Under the Illinois Professional Land Surveyor Act, licensed surveyors have a limited right to enter private property when performing a survey that has been contracted with the property owner or adjacent landowners. If a surveyor enters your property to place or locate monuments, they are acting within the scope of their professional authority. If you believe a surveyor is on your property without a valid reason, contact your local authority or an attorney.

Find a Licensed Illinois Surveyor for Your Project

Navigating Illinois land surveying laws is easier when you work with a licensed Professional Land Surveyor who knows your county and your situation. Find experienced Illinois PLS professionals in our directory at our Illinois land surveyor directory.

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Frequently Asked Questions

What law governs land surveyors in Illinois?

The Illinois Professional Land Surveyor Act of 1989 (225 ILCS 330/) is the primary law governing land surveying practice. It defines who can legally perform surveys, establishes licensing requirements enforced by IDFPR, and sets professional conduct standards.

Does Illinois require a survey to subdivide land?

Yes. The Illinois Plat Act (765 ILCS 205/) requires that any subdivision of land be platted by a licensed Professional Land Surveyor and recorded with the county recorder before any lots can be sold or transferred.

What is the Illinois Fence Act?

The Illinois Fence Act (765 ILCS 130/) governs shared fence costs between rural property owners in Illinois. It generally requires adjacent rural landowners to share the cost of maintaining a division fence equally. It does not require a survey before building a fence, but a PLS survey may be needed to determine where the shared boundary is.

How long is a land survey valid in Illinois?

Illinois law does not set an expiration date on a recorded survey. However, surveys more than 10 to 15 years old may not reflect subsequent changes to property lines, roads, or floodplain maps. Lenders and title companies often request current surveys for transactions involving older properties.

Can I use a GPS app to determine my property line in Illinois?

GPS apps and online parcel viewers give approximate locations only. Under Illinois law, only a licensed PLS can make a legal determination of property line locations. For any legal purpose (dispute resolution, permits, plat recording), you need a licensed surveyor.