How Pennsylvania Property Lines Are Legally Established
Every property owner eventually needs to know exactly where their land ends and their neighbor's begins. Whether you are planning a fence, adding a driveway, resolving a dispute, or simply satisfying curiosity, you need accurate information. The challenge is that some methods are reliable and some are not.
In Pennsylvania, only one method produces a legally binding result: a boundary survey performed by a licensed professional land surveyor. Every other method, including online maps, GPS apps, tax records, and informal estimates, gives you approximate information that cannot be used for legal purposes. This guide explains what each method provides and when you need the real thing.
Start with Your Deed
Your property's legal boundary is described in your deed. The deed description, called the metes and bounds description for most Pennsylvania properties, lists bearings and distances that trace the perimeter of your lot from a defined starting point. Reading your deed is the first step in understanding your property boundaries.
Find your deed at the county recorder of deeds. In Pennsylvania, deeds are public records and are available online through most county websites. Philadelphia County deed records are at the Philadelphia Recorder of Deeds at City Hall and online through the city's public records portal. Allegheny County deed records are searchable through the Department of Real Estate at alleghenycounty.us. Lehigh County and Dauphin County both provide deed search tools through their county websites.
Once you find your deed, read the property description carefully. Modern deeds from recorded subdivisions often reference a plat by lot and block number, which is straightforward. Older deeds, particularly in rural Pennsylvania counties and pre-20th century urban neighborhoods, use metes and bounds language that references old roads, watercourses, and monuments that may no longer exist. These older descriptions require a licensed surveyor to interpret correctly.
Use Pennsylvania County GIS Portals for a Starting Point
Pennsylvania's 67 counties maintain GIS (Geographic Information System) portals that display parcel boundaries, lot dimensions, and property ownership information. These portals are free and publicly accessible. They are a useful first stop for understanding the approximate shape and size of your property.
Philadelphia's parcel data is available through the Atlas mapping tool at atlas.phila.gov. Allegheny County's GIS is accessible at gis.alleghenycounty.us and shows parcel boundaries throughout the county with aerial imagery. Lehigh County provides parcel mapping through the county's online GIS viewer. Dauphin County maintains an online GIS portal that covers the Harrisburg area and surrounding townships.
The critical limitation of all county GIS data is accuracy. GIS parcel boundaries are derived from deed descriptions and digitized maps. They have not been field-verified by surveyors. In areas with complex deed histories, parcel lines in GIS can be off by several feet or more. Do not use GIS data to make decisions about where to place a fence, building, or other permanent structure.
Check for Prior Surveys at the Recorder of Deeds
Many Pennsylvania properties have been surveyed at least once. Prior survey plats are sometimes recorded at the county recorder of deeds, particularly for subdivisions and commercial properties. An existing recorded plat may show your lot boundaries, monument locations, and dimensions with greater accuracy than a tax map or GIS layer.
Search the recorder's index for your property by address, parcel number, or prior owner name. If you find a recorded plat, obtain a copy. A licensed surveyor can use a prior plat as a starting point, potentially reducing research time and cost for a new survey.
Note that a prior plat does not eliminate the need for a new survey if you need a legally current determination. Monument conditions change over time, lot configurations may have changed through subsequent deed transactions, and survey standards evolve. A prior plat is useful evidence, not a current boundary determination.
Look for Physical Monuments on the Ground
If a prior survey was performed on your property, the surveyor likely set physical monuments at the corners. Common monument types in Pennsylvania include iron pins (rebar or pipe driven into the ground), concrete monuments with a steel rod through the center, and aluminum caps set in concrete. These are typically found at the corners of your lot.
Look for iron pins flush with or slightly above the ground at the corners of your lot. Check near intersections of fences, edges of paved areas, and corners of buildings. Monuments are often buried under grass, debris, or paving over time. A licensed surveyor uses a metal detector and measuring equipment to locate buried monuments.
If you find what you believe is a corner monument, do not move it. Moving, removing, or disturbing a survey monument is a misdemeanor under Pennsylvania law. The monument is the physical evidence of a legal survey. Its location is meaningful only as long as it is in the original surveyed position.
When You Need a Licensed Surveyor
The situations that require a licensed Pennsylvania professional land surveyor are clear. You need a surveyor when you need a legal boundary determination for fence construction near the property line, when you are resolving a dispute with a neighbor about where the line is, when you are applying for a building permit and the municipality requires a plot plan showing lot lines, when you are subdividing your property under the PA Municipalities Planning Code, when a lender requires a survey for financing, and when you need an elevation certificate for flood insurance.
Verify any surveyor you hire at pals.pa.gov before signing an agreement. The PELSB license database shows current license status and any disciplinary history. The Pennsylvania Council of Land Surveyors at pcls.net provides a county-based directory of member firms.
A licensed surveyor will research your deed and prior surveys, visit the property to locate existing monuments and measure the boundaries, and produce a signed and sealed plat documenting the results. That plat is your legally recognized property boundary. Everything else described in this article leads you to that point.