You’ve probably stepped on one of these metal private property line markers on the sidewalks of New York City and didn’t think too much about them. But what are they exactly? Usually, the bronze plaque is embedded in the sidewalk and says something like “Property Line of XXX. Crossing by permission only. Permission revocable at will.” Meaning, you are allowed to cross a certain line on the sidewalk only with permission by the building owner, who can revoke this permission at any time.

Private Property marker plaque on NYC sidewalkPrivate property marker in front of 1211 Avenue of the Americas

Now that we’ve alerted you to them, you’ll probably start seeing them all over the place. Will you be suddenly taken out by security if you cross the line at the wrong time? A lot of people assume this is some kind of power grab by the buildings — the influence of corporate power over the faceless public. But it’s really a lot less sinister than that.

The usage of these markers is rooted in English land law from the pre-Revolutionary days called “easement by prescription” and applies to all kinds of land owners, not just corporate ones which are the most likely to put these signs out there. Under the law, use of land without permission for ten years gives ownership of that land to whoever encroached on those boundaries. So if you extend your fence into your neighbor’s property, after 10 years, you can claim that extra land as yours.

In these cases, the buildings place the private property line markers to prevent the public or the city from staking claim over that portion of the sidewalk that belongs to them. In one of the addresses we photographed, there is actually a real-life court case that has a connection to these markers.

New York Telephone Company Private Property MarkerProperty marker in front of the New York Telephone Company building in Tribeca

JT 1211 L.P. is the company that owns the building at 1211 Avenue of the Americas, also known as the News Corp Building where Fox News has its studios. In 2008, someone by the name of Charles T. Reiser sued JT 1211 L.P. for slipping on snow on the sidewalk in front of the building at 1211 Avenue of the Americas.

Reiser claims that his fall was caused by a misapplication or over application of salt by a service provider to the building. The full opinion of the court will take you down a rabbit hole you probably did not think possible over a slip and fall. But relevant to this story is the fact that Reiser fell on the portion of the sidewalk owned by JT 1211 L.P., not the public portion, which is why he could file a case against the company.

Possibly one of the most famous property marker in New York City, though not bronze, is Hess Triangle located in front of Village Cigars in Greenwich Village — a 500 square inch holdout on the sidewalk. Next time you’re walking around, take a look downwards and see what you might discover!

Next, discover what those bottle cap looking markers are on NYC’s streets, another discovery from our Cities 101 column.