"Leaves of three, let it be." I'm sure you have heard that saying and it will help keep you out of trouble, but not all leaves of three will set you to up with an itching rash. Poison ivy and poison oak will so those leaves of three need to be left alone. Can you tell which leaves of three in the included photos should be avoided so that the urushiol in all parts of the plant won't set off your body's immune system reaction to it that causes the rash? (Click on the images to enlarge them.)
And the answer is, unless you are part of the approximately 15% of the population that is not allergic to the urushiol in these plants, numbers 1 and 3 are poison ivy. Poison ivy grows as both a vine and a shrub. Number 2 is ivy treebine. While it releases an unpleasant smell when it is handled, it will not trigger a rash.