What is this?

While going for a Corona virus walk, in Barrington NH came across this on the trail.  

Guessing 10 ft tall, 8 by 8.  No door, solid all sides. Top, 1 ft seems to be removable. 

Entrance to Area 51?

How close are you to utilities/town?  It looks like an access for some kind of big hub for a utility.  Sewer pumping station, transformer, water main, etc.

Half mile or more from the road.  The land was originally going to ba a hunting reserve, assume it was put in when they were trying to build the place. I am guessing in the 80,70s or earlier....

Are you in a flood plane? Could be an inlet structure. 
 

edit: or a very stout deer stand. 

Is there sewer through there? If so I was going to suggest there might be a manhole on top and it might be to keep the sewer from mixing with flood waters. There are several similar here but they're usually round. 

From what I can see in those pictures...

Looks to be 8" nominal poured concrete wall,  large amounts of honey comb in the pour means it wasn't vibrated well which leads me to believe it wasn't meant to be particularly strong for a poured concrete structure.  It appears they used aluminum bucks to form it so I'm guessing 80's at the earliest.  Weird that they didn't bother to break the wall ties off. 

My guess is a pump house.  

In reply to dculberson (Forum Supporter) :

No sewer, not even at the main road.  Should have attempted to climb and checked the to .  Maybe next time.  

Barrington you say...I am in Somersworth.

Mystery solved. 

I have been told by the selt landtrust this was the base for a comunication tower.  Pre-cellular.  

Probably that space they trapped Superman in during the 60s.

vwcorvette (Forum Supporter) said:

Probably that space they trapped Superman in during the 60s.

I was thinking it was the flying saucer from Plan 9 From Outer Space.

remember the immovable object from Physics class?

First thing I thought of. Did you pee on it?

In reply to T.J. :

Just about to post that.  Glad I scrolled down first, for once.