It's one or the other, but which is hard to tell from the photo. I find Jacks' leaves are more to one side, while trilliums have the three leaves pretty evenly spaced around the stem.

Does this top shot help?

Looks like J-i-t-P to me. Trillium's veins are a little different.

I was going to say it looked like a trillium to me. So you are now right back where you started.

This site has a photo of J-i-t-P leaves that show their one-sidedness.
http://10000birds.com/jack-in-the-pulpit-arisaema-triphyllum.htm

This photo shows how the trillium leaves are more evenly spaced around the top of the stem.
http://www.fs.fed.us/wildflowers/plant-of-the-week/images/redtrillium/trillium_erectum_mpistrang_lg.jpg

Thanks for the input. I put a garden stake next to it. I guess at this point I just wait until it blooms?

It may be a year or two until it blooms, and depending on how moist or dry the soil is, it may die back in the summer. But it will return next spring, so the stake is a good idea to help you remember where it is.

I have trillium and jack. Its a jack baby.:)