Certified GKH Gardening Expert
It is very hard to say from a single picture, unfortunately. There are some ways that you can ID the plant, but do know that there are many look-a-likes.
This appears to be first year growth, since I'm not seeing any alternate growth. Check any stems for purple spotting, as this is a really good indicator that you have poison hemlock. Another option is taking photos or samples to your nearest extension service. They can help you figure out what you are looking at.