Yellow nutsedge I believe.

Wow Carol, that was fast! I looked it up, and it is a noxious weed. I read that they are a tropical weed, common in California. Wonder how he got to Illinois>? Anyway...
Away he goes to the burn pile! Thanks.

Christa, welcome to GardenWeb. We hope to see you back here many times.

Yes, that's yellow nutsedge, a VILE weed! Pull it up carefully and dispose of it in the trash....not the compost pile. Keep a close watch for this sedge in your lawn as well as your garden and planting beds. Pull pull pull!

Formally known as Cyperus esculentus.

After just a few leaves, it grows a "nut" (a small tuber) underground: stored energy to grow more plants. So it's to your advantage to pull nutsedge as soon as you see it, before it grows any "nuts."

Nutsedge can also spread via seeds....

In the lawn you'll notice it by its color (lighter and yellower than most grass) and size (a bit taller than the grass, when it's time to mow).

Actually, yellow nutsedge is in all the lower 48 states except Montana and Wyoming. In my county it's noted as "noxious."

You can pull them , but you'll leave the 'nut' behind to keep growing. Use a trowel and dig way down beneath the root zone.

Have fun!

Next time, try to ID weeds before they get very established.

There is a poison called Sedgehammer (comically enough) the local radio guy recommends.

I have the stuff. It is only second to the bermuda / zoysia weed I have spreading all over the place in terribleness.