Is no one else going to talk about how weird it is to see a square manhole cover? Now there's a risk of dropping the cover down the hole due to the shape.
It's probably a hand hole for accessing a pipe or cable junction, likely smaller because it's where business or homes hook in. I work for an ISP, and most of ours are about this size
Setting square tiles or paving stones around a circular cover is a pain in the ass.
But it wouldn't be the first time the US is weird, like the whole imperial measurements thing, so whatever. Or maybe you live in a state that decided square manhole covers were biblically incorrect.
I see small square junction box things like this all the time in California. Mostly in-between where two homes' lawns meet. The one I had in my lawn before I moved to an apartment sucked because it was slightly raised from the grass and was in an awkward position to try and get the mower around.
For a while in the programming world "why are manhole covers round?" was a common question to be asked in interviews. I had no fucking clue the first time I was asked, but subsequently I would put on my deep pondering face and reason through it out loud and arrive at the correct answer, which never failed to impress the interviewer. After a few years I started owning up to the fact that I (and everyone else) had already heard that question.