I have little perfectly round holes in my yard... do you know why?

An inch or so across? Maybe 6 inches deep? Could be mice burrowing in on a cold night.

Since I am not sure how big the holes are, I found a website that can give you more information and help you figure out what it is. My first guess is mole hole.

It is most likely moles ,voles or chip munks

I have them in my yard also. My husband tells me they are from the skunk looking for food.

We have what we call black racer snakes (non-venomous), that are long and thin like a garter snake here in the south. They mostly live in, burrow in, the ground and the round holes are an indicator. They stay underground about 70% of the time. They like to climb trees to get at the bird eggs. They also eat frogs, lizards, small rodents and other snakes. They can and will bite if antagonized and are very active in the daytime. As soon as you see a hole, fill it in ASAP. Filling these holes require the snake to move on to other places to live, especially if they are down inside of the hole. That's my best guess! Hope this helps.

The holes, if they are an inch or so around, might be cicadas.

They are between a half inch and inch across I dug in one but found nothing.

They are in our woods and at the river....gives me the creeps...especially if is related to a snake 😬