This is a question I have been asking myself since like forever. Because I don't know. I used to think Home was where I grew up but I left there long ago. Decades ago. 

When I first left the ol' home town, I didn't go far away or stay gone too long. I'd occasionally drift back in and do a lap around it and then through it and notice the things that had changed. Not too much. 
Gone a bit longer, I would roll back into town and notice that more had changed. The people that still lived there didn't notice it as much but I sure did. "Hey! That bar what usta be there is gone!" or "Lookit all these new houses!" or "What's that building over there they just put up?". Those were the big things. But I saw the little things too. Signs that had changed. Businesses that were under new ownership. Everything. Nothing escaped my eye because I had grown up with an innate interest in tracking cultural and societal things and clearly remembered the way the town had been before. 
Then I was away for almost a decade. If my occasionally coming back and seeing what had changed had been a bit of an eye opener, this time I hardly recognized my old stomping grounds. Lots had changed, so much so that it certainly didn't feel anything like the home town I had stored in my memory. That place was most definitely gone. 

The people that were living in 'my' home town I didn't recognize. And they didn't recognize me. Talk about culture shock! Didn't they know? No- they didn't. They didn't know anything about what had transpired at all the places where I had experienced seminal growing up events. To those they were oblivious. And on top of that, to add insult to injury, they sauntered around like they owned the place, which really ticked me off. Deep inside I wanted honor, homage, respect, and tribute from them but I got nothing. In their eyes I had relinquished my claim on the territory, and sacred ground or not, it was theirs now. They had clearly taken over. I was free to move back, of course, but the culture and vibe had shifted a great deal to match the newcomers. Whatever that hometown 'something' was that I had grown up in, and helped in my unique way to foster, was gone forever.
To experience that sort of thing really brings it home to you that you don't matter much. Whatever influences you have are temporary. It was almost as if I had died. There's a line in the movies: "You're dead to me, man!" which means you're 'invisible', 'gone', 'out of my consciousness', and I certainly felt dead to my ol' home town. 

But there are other towns that I have called 'home' since then, plenty of those. I inhabited them but they were more or less long term campsites than anything approaching Home. So I really don't know what Home is, or where it is. Or if it even exists. Maybe it does for some people, like Walton's Mountain was Home for The Waltons, or LA is Home for the 'homies' that live there, or New York City is Home for the people that can't possibly live anywhere else. I've heard those places called Home.

They say 'you can't go home again' and that's true, 'cuz things change, but in my case I wonder if I've ever been at Home so how would I even recognize Home were I to find it?
It's not in some other country. I've been to many of those and they felt less like Home. I'm an American, I know that. But where in America is Home?
Seeing as nothing specific comes to mind, or has ever come to mind, I lay claim on the whole damn country! That feels about right.

America is my Home and ‘sea to shining sea’ is my backyard!