Find Property Lines by Address

A satellite can photograph a roof, a driveway, a fence and a hedge. It can’t photograph a property line, because a property line isn’t a physical thing. It’s a boundary written down in records.

So a map that appears to show property lines on satellite imagery is really showing two separate things stacked on top of each other. The photograph shows what exists. The parcel layer drawn over it shows where the records put the edge of the lot.

That distinction is worth holding on to, because nearly every question people have about online property lines comes back to it. Coverage, accuracy and alignment are all facts about the second layer, not about the picture underneath.

It’s the first thing almost everyone does. You look at the back fence, or the hedge, or the point where the mowing stops, and you take that to be the edge of what you own.

Sometimes that’s exactly right. Plenty of fences were set on the line by somebody who knew where the line was. Plenty of others weren’t, and the reasons are ordinary. A fence gets built a foot or two inside the boundary so the far side can be maintained without stepping onto a neighbor’s land. A previous owner put it where the ground was easy. A hedge was planted for privacy rather than for surveying. A driveway was widened and the lawn edge moved with it. Somewhere in the middle of all that, an easement or a setback runs across land that is genuinely yours and still has rules attached to it.

A parcel overlay helps here, and it helps most in the case that is easiest to miss: where a fence and a boundary agree along one side of a property and quietly part company along another. What it can’t do is settle the question, because it is recorded reference data rather than a determination of where the line legally runs.

Parcel line overlays are currently available for U.S. properties only. Measuring works anywhere in the world.

The parcel layer and the photograph underneath it are made by different people, at different times, by different methods. Nothing in the process forces them to agree.

Parcel geometry is usually digitised from recorded documents, plats and older maps, then fitted to the ground as well as the available control allows. Aerial imagery is captured on its own schedule, stitched together from many frames, and corrected for terrain and camera angle. Each one is doing its own job carefully. Neither is being drawn against the other, and the two can be described on slightly different map projections before they ever reach a screen.

So an overlay landing a few feet off a fence doesn’t prove the fence is in the wrong place, and it doesn’t prove the parcel record is wrong either. Most of the time it means the two layers disagree about where one point on the ground belongs. That’s a mapping fact, not an ownership fact, and the tell is usually that the whole boundary is shifted by roughly the same amount in roughly the same direction.

In conversation these are used interchangeably, and most of the time that’s fine. Where it stops being fine is when the source matters, because the records behind them are not always the same records.

Definitions also vary by jurisdiction. A parcel drawn for tax assessment and a lot drawn on a subdivision plat are answering slightly different questions about the same piece of land, and in some places the two are maintained by different offices. If a document uses one of these terms precisely, it’s worth finding out which one it means.

Parcel geometry starts with local government. County assessors, recorders and GIS departments maintain the parcel maps for the land they’re responsible for, largely so property can be assessed and taxed, and most of them publish that data in some form.

There are a few thousand of those offices in the United States and they don’t share one system, one schedule or one standard. That’s the problem data providers exist to solve: collect what the local sources publish, normalise it into one shape, and pass it on to the maps people actually use. FindPropertySize draws its parcel layer that way, as a mapping and reference layer over the imagery.

Which is why coverage and freshness vary from place to place. Some counties publish detailed geometry and revise it often. Some publish less and revise it rarely. If no boundary appears for a property, that’s usually a fact about what’s available there rather than about the address you typed, and you can still measure the property from the imagery.

Parcel line overlays are currently available for U.S. properties only. Measuring works anywhere in the world.

Not as a feature you can switch on. There’s no property boundary layer in Google Maps and no setting for one.

What people are usually remembering is one of two things. Zoom in far enough in some areas and the base map draws faint grey lines around individual lots, which come from public data and are there as map detail rather than as a boundary product. Or they’re thinking of Google Earth Pro, where you can import a KML file from a county GIS site and see that county’s parcels over the imagery.

Both of those work as far as they go. Neither gives you a boundary you can look up by address in every area, which is the gap a dedicated parcel map fills, and the same gap a county GIS portal fills if you’re willing to learn a different website for every county.

There isn’t one number, and anybody quoting you a single figure for the whole country is guessing. Accuracy is a property of the parcel record for the place you happen to be looking at, and those records were made in very different circumstances.

Geometry digitised from a recent, well controlled survey lands closer than geometry traced off a hand-drawn plat. A parcel nobody has revisited since the subdivision was recorded carries whatever was known at the time. Long rural parcels described by metes and bounds accumulate more error along their run than a small platted rectangle does. And the imagery underneath has its own alignment, which is a separate question from whether the record is right.

The practical version: an online boundary is usually good enough to tell you what shape a lot is and roughly where it runs. It isn’t good enough to tell you where to put a post.

A parcel boundary tells you where the records put the edge of the lot. A measurement tells you how much of something is there. Those two come apart more often than people expect.

Somebody quoting sod cares about the lawn, and the lawn is a fraction of the parcel. Somebody pricing a resurfacing job traces the driveway and nothing else. A homeowner checking acreage wants the whole parcel and nothing less than it. Somebody planning a shed wants the boundary visible the entire time they’re measuring something completely different, because the boundary is the constraint and the shed is the work.

So the two are separate things in FindPropertySize. The parcel layer is context you can leave switched on while you work. What you trace is your decision, and it can follow the boundary, sit well inside it, or ignore it entirely.

An online parcel map is not a legal survey, and no amount of zoom turns one into the other. A survey is a licensed professional locating the boundary on the ground and standing behind that determination.

The situations that call for one are fairly specific. A disagreement with a neighbor about where the line runs. Construction close enough to a boundary that a couple of feet changes the answer. Fence placement where exact position matters. A legal description for a document. Locating the official corner markers. A transaction where boundary certainty is part of what’s being agreed.

Short of a survey there are other authoritative sources worth knowing about. Your deed carries the legal description of the property. A recorded plat shows the lot as it was laid out. If the property has been surveyed before, the corner pins may still be in the ground and the survey itself may be on file. County records are where most of that lives, and they are a better place to start than any map.