Pictures would be nice. Are they only shallow holes or are they tunnels.
Could be gophers, rats, ground squirells.

Sounds like "ant lions" They are the larvae of some insect and trap and eat ants and other insects that fall in their cone and can not get out the steep sides. You can catch them if you scoop out the cone and dirt below and they wriggle downwards. I have never heard anything bad about them. We have them all over and the kids catch them for fun then let them go. I am curious if anyone knows more or what they grow into.

Sounds like nite crawler burrows to me not harmful at all.

At 2" diameter it won't be nightcrawlers.

It looks just like this!!
http://en.wikipedia.org/wiki/File:Antlio...

This is what the area looks like! but I don't think we have those Antlions up in the Northeast. I could be wrong though.

http://www.asknature.org/images/uploads/...

Take some pictures to your local county extension agent, they should be able to help.

You need to give use the complete link not the one that ends ...

I'm voting antlion. I grew up in the South, used to see dozens of the little pits under the edge of porches, eaves, any sandy soil protected from the weather. If you put an ant in one, the antlion at the bottom will throw sand at it to knock it down within reach. Mealtime!

the best way to tell is the size of the hole, and the composition of the hill - tiny particulate matter usually means ants, little green things like capers are grubs, little balls of mud are almost always earthworms.

warmblooded pests usually leave holes bigger than you describe your hills to be, and ant lion craters tend to look like, well, craters.

a sticky trap set amongst them might provide some clues, though : )

Down here in Texas the pest is the Armadillo. Yep, cone shaped 'holes' everywhere. They are seeking worms/grubs. Hate them......they can ruin a lawn.

could be moles or voles as well
we get little dirt hills where they come up in our lawn--maybe not perfect cones
I did not try the links for pictures

we have terrible time getting rid of them from our yard--
have tried the dry bait pellets and also spraying the yard with castor oil--was out there yesterday doing that...

if it is moles/voles--and you use the spray--
you should spray only part of the yard and try to move them outwards in sections--
like one third--then add the next third--then the final one--that encourages them to evacuate...

They're cicada killer wasps

http://ww2.lafayette.edu/~hollidac/cicadakillerhome.html

I've used many things to rid my property of these (remember they return yearly!) I had some lighter fluid after I purchased a gas grill a number of years ago. Works well, after a few squirts down the hole at dusk poof and the little buggers are toast.

Bob

Well, Bob, what in the hell damage are these little fellows doing that you feel disposed to kill them? Then there are those gastly earthworms that leave little piles of dirt in your grass. That lighter fluid otto kill them thar worms.

The ant lion works/builds traps in very fine soil, it will be almost like dust. Their traps are in DRY dirt. The holes originally described could be the work of skunks. They burrow for grubs.

In our lawn there are tunnels just under the grass. We live in South Louisiana. On our walkway there is a pile of dirt next to the stepping stones which leads to several raised tunnels in every direction and pattern. It seems to be a round tunnel I can shove a broom handle into. Could this be a snake of some sort?

They kill Termites and Ants..... They are a helpful insect. http://lancaster.unl.edu/pest/resources/antlions.shtml 

In the south esp la. & tx they have crawdad chimneys. Drop a rock in the chimney and hear water.

@kenanlin your post is from 2011 sadly but what you have (had) there is moles.