Where does public property end and private begin?

I'm asking in regard to the United States, but if anyone knows for other countries, feel free to chime in as it may help someone else.

I'm also not trying to create a thread to talk about the legality and/or ethics of shooting _____ from a public/private location.

Basically, I just would like to know where are the boundaries of photography of a public place lie. Is it strictly based to parks, sidewalks, and the streets? What about the shoulder's on the road? What if there aren't any shoulders or sidewalks? Is there a specific amount of grass that is deemed public for foot traffic? What about the grass between the sidewalk and the street? Is it illegal (jaywalking or other?) to stand or walk on the edge of the street? What about medians?

It's going to vary all over the place, even within the US. Most roads run along specific rights of way, but the width of that right of way will vary with the place, and even with the road. Sidewalks, too (even if there is no sidewalk, the RoW may exist for one to be placed later). And traffic laws will govern jaywalking or walking along the street/road (for instance, the Interstates have general prohibitions against walking, bicycling or horseback riding along them).

The definition of public property an photography are two different things. Public property generally is anything owned by a government or government agency and offered for use to the public at large. Therefore a street or highway is public property but if your standing in the middle of a highway taking pictures, your very likely to get a talking too. Other places are controlled as well. For instance, the White house is public property and there are tours given so there is access to the public. However photography last time I went was not allowed.

Like Jon said....there isn't going to be a simple answer here. For example, I live in a small private subdivision. Each of us owns to the center of the street in front of our residences. There is no "public" access per se...only access granted to fellow homeowners under the covenant in the deeds. The best bet is going to be to check with local authorities if there is a question.

This is really a great question.

Public LANDS - You may need a permit
http://www.largeformat​photography.info/photo​-permits/

Here's a good PDF to download:
http://www.krages.com/​phoright.htm

A good book - And I was one of her clients, highly recc.
http://www.photoattorn​ey.com/
http://www.photoattorn​ey.com/products.html

Thanks guys. I'll definitely check out those sources. I wonder if I can find anyone associated with the government that can fill me in on the local ordinances.

That will call for a trip to your local offices where the local ordinances are written and stored.

But an important tip: Gatekeepers usually feel a civic duty to keep the gate closed even when their job is to keep the gate opened. These days, bureaucrats tend to believe there is something inherently dangerous about taking photographs outside a studio, so don't directly ask about photography until after you've gotten the actual word on "public or private."

If you mention photography right upfront, then you're going to get an answer affected by their feelings on public photography...not on the specifics of "public or private" land.