Here is a closer look at the leaves

If it isn't it sure is close! The final test is to dig up a root and slice it in half lengthwise. It will have horizontal chambers. Caution! This plant and the roots are extremely poisonous! The roots are the most poisonous part of the plant.

Hemlock likes moist sites, streams and ditches.

hortster

Thank you, hortster. This was growing near a ditch but on the edge of someone's field. I would love to march right over and dig some up but the property owners might object. I just can't find photos where the leaves of this quite match up with water hemlock.

Don't worry. That isn't hemlock. It's an Elder Tree, Sambucus species. If you want verification post it on the Name That Plant Forum. I think you'll find they agree.

Here is a link that might be useful: Name That Plant

floral_uk, I do agree. In fact, I just came over here to suggest it might be common elderberry.

No, that isn't hemlock. Hemlock has smooth cylindrical stems, not ridged hirsute ones. It also usually has purple blotches on the stems.