Question
I live on Long Island in New York and am having a problem with tunnels in my lawn.  I observed a big tunnel in my lawn (I can almost fit a closed fist in it) and am not sure what is in it.  I do not have a big mound of dirt at the hole and the hole goes about 2 feet deep before making a turn.  While walking around the lawn I feel parts of the lawn are raised but nothing that is visible to the naked eye.  I have set a havahart trap by the entrance and the only thing I have caught is squirrels.  Is it possible to have ground squirrels in New York?  Most trappers I talk to around here say squirrels dont dig burrows.  If not a squirrel then what is it and how do I get rid of it?  Thanks

Answer
Woodchucks are ground squirrels but the hole seems too small for that species. Besides, if it was, he is hibernating by now.

Put the cage trap away for now. My suggestion is to see if the hole is active by corking the hole with rolled up newspaper or placing thin sticks across the openning. Check the hole daily to see if the sticks are moved or the paper pushed out.
It could be a sink hole.

I would hope that ALL the trappers say that tree squirrels don't dig burrows.

As for the squishy soil, sounds like moles. The problem with trapping this time of year is the moles are likely deep to get below the frost line.

I suggest being patient and employing my hole test. Then if it is active, we can move to plan B. Otherwise, if after 5 days of good weather, with no action, then can consider back filling the hole with dirt.

Otherwise, info on identification can be had at http://icwdm.org Control info as well. I just think you should wait first as right now I don't even know what your damage is caused by. Just not enough info.