Poison ivy is a plant that has three parted compound leaves. The hard thing about saying what it looks like is that aside from this fundamental "leaves of three" is that almost every other descriptor is variable. The leaves may be stiff and leathery, or thin and supple. The leaves may be somewhat hairy or completely hairless, they may be shiny or dull. The leaf edges may be toothed, wavy or neither. The plant grows as a vine, a small freestanding plant or as a dense shrubby thicket which may reach heights of five to ten feet! The one good point in all of this uncertainty is that few other plants have three parted compound leaves! So, if you see "leaves of three", as the adage goes, "leave them be!"
Poison ivy can be found growing in open woods (you can see it all along the Nature Trail!), in thickets, in fence rows, along roadsides and in sites that have been disturbed or which are undergoing active early succession. Human activity seems to encourage and facilitate its growth and dispersion
When hiking in potential poison ivy locations, bring along an anti-poison ivy spray (they sell it at Walgreens). It only works if you get exposed to the plant. It isn't like sunscreen and bug spray. If you are exposed, you wash the area with soap and water as soon as you can and then spray the stuff on the affected area. It will lessen rash. If I use this stuff, the rash is gone within 2 days - but that is me.