What the Heck Are These?

So, I’m walking down the sidewalk close to my house this afternoon, and I see these:

These pillars are in a triangular position.

I’ve seen them plenty of times before and have always wondered what they were, but today I decided not to be lazy by taking a few pictures and uploading them to this post.

So, what exactly are they? My initial guess was that perhaps they were old border markers from back during the Revolutionary War. There’s a town near here called Geneva where the old Massachusetts border used to be, so I felt that it was a valid educated guess.

But what are they? The question has been bothering me since this morning, and whenever I Google them, I’m directed to some companies that are completely irrelevant to my quest for knowing the truth!

Do you know what they are? If not, what do you think they could be?