What is a plat map, and how do you read one?

A plat is a recorded drawing that divides land into lots and dedicates the streets, easements and common areas that go with them. It is filed in the county's plat book and referenced by deeds. If your deed says "Lot 14, Block 3, Cedar Ridge Subdivision," the plat is the document that defines what Lot 14 actually is.

Plat, survey and GIS map are three different things

• Plat: recorded, legally operative, defines lots and dedications at the time of filing.
• Survey: a licensed measurement of one parcel as it exists today, usually not recorded.
• GIS parcel map: the county's assessment layer, useful for orientation and wrong at the edges.

Never treat a GIS boundary as a property line. It is drawn for tax administration and can be off by many feet.

Reading the drawing

Each lot line carries a bearing and a distance — something like N 42° 15' 30" E, 214.60'. Curves show a radius, arc length and chord. Dashed interior lines are usually easements, labeled with a width and a purpose: utility, drainage, ingress and egress. Small circles or squares at corners mark monuments set or found.

Read the notes, not just the lines

The block of text on the plat is where the real restrictions live: no-build setbacks, drainage maintenance obligations, septic reserve areas, wetland buffers, private road agreements, and references to a separate declaration of covenants. Buyers study the geometry and skip the notes, which is exactly backwards.

Where to get it

Start with the county recorder or clerk; many publish plat books online for free. If the parcel was never platted, the deed's metes and bounds description is the controlling document instead, and older subdivisions may have amended or replatted sheets that supersede the original. Pull every version before you rely on one.