Can anyone tell me what this is?!

Mybe it's a bomb shelter. Open it up and look. I'd have too. Have a great day Hardluck.

It looks like the lid that goes to cistren. It is like a well. If you take the lid off, it is probably cemented, or full of dirt. They are supposed to be filled in if not being used and is illegal in most towns, to use.

when i lived in new jersey i had one,it's a surface well most likely 50-75 foot used for irrigation purposes not deep enough for drinking we also had a deeper artisian well for drinking 250 foot deep which was outstanding during the hot summer months because the water was alway's colddddd.these well's were used before the homes were hooked up to the city water. i filled mine in also when i started having children.

There is a good possiblity that it was a well in its time. If you have an older house in an older subdevision, they might have had wells then but have now been put on sewers as the city has grown. If not that, then it could be a dranage tank. I know my boyfriend has something like that in his yard but it's a lowered peice of concrete that could twist your ankle if you didn't know it was there. He wanted to level it off one day but was told not to as it was for the dranage in case his pool overflowed. Maybe the way your yard slants, that water and snow drain into that so you don't have a flood in your house. If you are really concerned as to what it could be, my suggestion is to have someone from the city come out and look at it for you. Let them know that you would like to know what it is and you are concerned about it as it could be a potental hazard and you want any children in your yard to stay safe. Is it someting you are aloud to cover up or remove? They might not charge you if you let them know how concerned you are about it.