Finding Property Lines in Maryland
Maryland property owners have several options for researching where their property lines are. Free online tools give useful general information, but only a licensed land surveyor can establish legally binding property corners. Here is how to approach both.
Free Online Resources for Maryland Property Lines
SDAT Property Search
The Maryland State Department of Assessments and Taxation (SDAT) maintains a property database at sdat.dat.maryland.gov. You can search by address or owner name and pull up your property account record, which includes a parcel map showing approximate boundaries. The SDAT map is drawn from recorded plat data. It is useful for identifying your parcel number and seeing your lot in context with neighboring properties.
Maryland iMap
Maryland iMap at imap.maryland.gov is the state's geographic information system portal. It includes a parcel viewer that overlays property boundaries on aerial imagery. You can turn on layers showing parcel lines, water features, roads, and jurisdiction boundaries. The parcel layer uses the same data source as SDAT and has the same limitations: lines are approximate and can be off by several feet.
County GIS Portals
Many Maryland counties maintain their own GIS systems with more detailed local data than the state portal:
- Montgomery County: MC Atlas (atlas.montgomeryplanning.org) offers a detailed parcel viewer with property information.
- Baltimore City: The Baltimore City Open GIS (gis.baltimorecity.gov) provides parcel boundaries, assessments, and property data.
- Prince George's County: iMap (imap.princegeorgescountymd.gov) provides parcel and zoning information.
- Frederick County: Frederick County GIS at apps.frederickcountymd.gov offers parcel data and aerial imagery.
Maryland Land Records
Recorded plats and deeds for Maryland properties are accessible through the Maryland Land Records database at mdlandrec.net. This is maintained by the Maryland Judiciary and gives access to deeds, plats, and other recorded instruments. You can search by county, name, or document type. Reviewing the recorded plat for your subdivision shows the official dimensions and layout as filed with the county clerk.
What Online Tools Cannot Tell You
Online parcel maps show where lines were drawn in a GIS database based on historical plat data. They do not reflect actual field conditions. Property boundaries in older neighborhoods, rural areas, and waterfront properties can differ from GIS representations because:
- Old deeds used measurements and references that do not translate precisely to modern coordinates
- GIS data may not incorporate the most recent survey or boundary adjustment for a parcel
- Parcel lines are often digitized from old paper plats, introducing small errors
- Waterfront and tidal boundaries change with shoreline changes and periodic FEMA remapping
For any decision that depends on knowing where your line actually is, including fence placement, construction near a property line, or resolving a dispute, online tools are not sufficient.
When to Hire a Licensed Surveyor
Hire a licensed land surveyor when:
- You are building a fence, deck, addition, or shed and need to confirm setbacks from the property line
- A neighbor disputes where the line is
- You are purchasing property and want legal certainty about the boundaries
- You are subdividing or combining parcels, which requires a recorded plat from a licensed PLS
- Online tools show your parcel as having unusual dimensions or configurations you want to verify
A licensed surveyor will locate physical monuments placed by prior surveyors, research the deed chain, measure the parcel, and provide a certified plat. That plat, signed and sealed by a Maryland PLS, is the legal record of your property boundaries.
Find a Licensed Surveyor in Maryland
Search our Maryland land surveyor directory to find licensed professionals by county. All listings are sourced from state licensing records maintained by the Maryland State Board for Professional Land Surveyors.