How to Read a Plat Map: A Line-by-Line Guide

A plat looks like a tangle of lines, angles and abbreviations, but it is one of the most precise documents in real estate. Every line has a direction and a length, every lot has a number and an area, and every note on the sheet was required by someone. Once you know where to look, a plat answers most questions about a lot before anyone visits it.

This guide walks a recorded subdivision plat from the title block to the recording stamp.

What a plat is, and when one is required

A plat is the legal map that creates lots. In Texas, Local Government Code §212.004 requires an owner inside a city or its extraterritorial jurisdiction who divides a tract into two or more parts to lay out a subdivision to have a plat prepared, whether the division is made by plat, by metes-and-bounds deed or by contract. Parts over five acres, each with access and no public improvement dedicated, are excepted.

The plat must describe the subdivision by metes and bounds, show the dimensions of its streets, be acknowledged like a deed and be recorded with the county clerk. The Property Code bars the clerk from recording one that has not been approved. Florida's statute puts the standard well: a plat is "a complete exact representation of the subdivision."

If you are unsure whether you are looking at a plat, a site plan or a sales map, our guide to plat maps, site plans and site maps sorts them out.

Start with the title block

The title block names the subdivision and gives its legal description. Houston's plat rules require a unique subdivision name and a description that includes the county, survey and abstract number. Texas never adopted the federal township-and-range system, so its land is located by original survey and abstract.

Next to it you will find three tools for reading everything else:

• North arrow. Houston requires north at the top of the sheet.
• Scale. Both a numeric scale and a graphic bar. Dallas asks for 1 inch = 30 feet, or the largest practical scale no smaller than 1 inch = 60 feet; 1 inch = 50 or 100 feet is also common.
• Vicinity map. A small locator map, often marked N.T.S., not to scale.

The three ways land is described

The Bureau of Land Management's surveying course names three systems, and a plat uses at least two of them:

• Metes and bounds describes a boundary as a series of bearings and distances from a starting point. The plat's outer boundary is written this way.
• Lot and block describes land by reference to a named, recorded subdivision: Lot 7, Block 2, Cedar Ridge Section 2. Once the plat is recorded, that is the legal description of every lot in it.
• The rectangular survey system divides public-land states into townships of 36 sections, each one square mile or 640 acres. Our glossary entry on section, township and range covers it.

Bearings and distances

Every straight line on a plat carries a bearing and a distance. The BLM defines a bearing as the angle from north or south toward east or west, so a line in the northeast quadrant at 50 degrees has a bearing of N 50° E.

Read the boundary label on our sample, N 81°18'49" E 437.01', in four steps:

1. Face north.
2. Turn 81 degrees, 18 minutes, 49 seconds. There are 60 minutes in a degree and 60 seconds in a minute.
3. Turn toward the east.
4. Walk 437.01 feet.

Dallas requires bearings to the second and distances to the hundredth of a foot. The plat also states a basis of bearings, the reference everything is measured from. Houston's standard note ties bearings to the Texas Coordinate System of 1983, South Central Zone.

The boundary description starts at the point of beginning (P.O.B.), sometimes reached from a point of commencing (P.O.C.) at a known corner, and runs around the tract until it closes on itself.

Curves and the curve table

Curved lines cannot be described by one bearing, so a plat labels them C1, C2 and so on and lists them in a curve table. Florida's statute requires the radius, arc length and central angle for curved lot lines, plus the chord and chord bearing for street centerlines.

The values check each other. A curve with a 50-foot radius through 90 degrees has an arc length of 78.54 feet and a chord of 70.71 feet. The arc is always longer than the chord.

Lots, blocks and reserves

Lots are numbered consecutively within each block, and the plat gives each lot's area, usually in square feet. An acre is 43,560 square feet; our square feet to acres converter does the division.

Land that is not a buildable home lot is a reserve, labeled by letter. Houston requires any land not restricted to single-family use to be shown as a reserve with its acreage, restricted to a stated purpose such as detention or open space. An "unrestricted reserve" is land whose use has not been decided. Houston's standard note says a restricted reserve's use may not be changed without Planning Commission approval.

Streets, easements and building lines

Each street is named with its right-of-way width, such as a 50-foot or 60-foot R.O.W.

Inside the lots, two dashed lines limit what can be built:

• Easements are strips other parties may use for utilities, drainage or access. A Harris County plat defines an aerial easement as the space from a plane 16 feet above the ground upward. Dallas requires each easement to be labeled as created by this plat or by separate instrument, and the separate ones are easy to miss.
• Building lines are set back from the front lot line. Houston's Chapter 42 bars any improvement that needs a building permit from the building line area, and where deed restrictions set a larger line, the deed restrictions control.

Houston's standard notes say utility easements must be kept unobstructed, and that utilities may remove a fence in one at the owner's expense. Check the easements before planning a fence or a pool.

Common plat abbreviations

These come from a Harris County plat legend, a Dallas plat and Caltrans' curve sheet. Every plat should define its own: Houston and Florida both require a legend of all abbreviations and symbols used.

Monuments, flood zones and other notes

Monuments are the physical markers the plat is tied to, usually iron rods with plastic caps set at lot corners. Texas rules require a set monument to be marked so it traces back to the surveyor who set it.

Flood zone notes give the FEMA flood insurance rate map panel number and its effective date, which many plat checklists require. On FEMA maps, high-risk areas are zones beginning with A or V.

General notes are where restrictions live: "all lots are restricted to single-family residential uses," drainage covenants, and the scale factor between grid and surface distances. Read every note. A plat note is part of the recorded instrument.

Approvals and recording data

The bottom of the sheet carries the signatures that make the plat official:

• The owner's dedication, which gives streets and easements to public use.
• The surveyor's certificate and seal.
• The approvals, such as a planning commission, a county engineer or a commissioners court.
• The clerk's recording stamp.

The recording reference is how you find it again. Harris County records plats by film code in its Map Records; many counties use a volume or book and page, or a document number.

How to find a recorded plat

Plats are kept by the county clerk or recorder, in the map or plat records. Harris County's online Maps and Condos search, for example, takes a file number, film code, volume and page, or a description. Start from the deed: its legal description names the subdivision, lot and block and usually the recording reference.

The appraisal district's parcel map is not a substitute. The Harris County Appraisal District's viewer says its map is not an on-the-ground survey and shows only approximate boundaries. Our guide to subdivision platting in Houston covers how a plat gets approved and recorded.

A plat is not a survey

A plat is drawn before the houses exist. Dallas's checklist tells surveyors not to show topographic features such as fences, paving and buildings on a plat. So a plat cannot tell you where a fence actually sits or whether a driveway crosses an easement.

A boundary survey, or an ALTA/NSPS survey for a commercial deal, can. The 2026 ALTA/NSPS standards require the surveyor to show walls, buildings, fences and other improvements within five feet of the boundary, possible encroachments, and the setback lines shown on the recorded plat.

Replats, amending plats and sales maps

A recorded plat can be changed, but only formally. In Texas, a replat under §212.014 needs approval and does not amend or remove covenants or restrictions. An amending plat under §212.016 can correct an error in a course or distance or move a lot line to fix an inadvertent encroachment, without notice, a hearing or other owners' approval. Always check for a later plat over the one you are reading.

A sales map is not the plat either. Florida requires every plat to say that the recorded plat is the official depiction and will not be supplanted by any other graphic or digital form. A builder's colored lot map is marketing; the plat is the record.

Where a map fits

Most buyers never open a plat. Its useful parts, lot numbers, areas, frontages, easements and reserves, can be carried onto a map anyone can use.

An interactive plat map is built from the recorded plat itself, so each lot keeps its legal number and dimensions while buyers see availability and premiums on the same lot. Our guide to turning a plat map into an interactive map explains how.

The Bottom Line

A plat is the legal record of every lot in a subdivision, and it can be read in order. Title block and scale first, then bearings, distances and curves, then lots, reserves, easements and building lines, then notes, monuments, flood zones and recording data.

Read the notes as carefully as the lines, check for later replats, and use a survey for what is actually on the ground.