This is more of a view point stop then a hike. Gibbon Falls is near the West Entrance of Yellowstone. It is certainly worth the stop as it is a beautiful falls, and it is fun to walk the whole area so that you can see the falls from different angles.
When I first arrived at Yellowstone I entered through the West Entrance just before dusk and Gibbon Falls was one of the first features I saw, besides an Elk I spied that was a ways off in a field.
My daughter Marina did not arrive for another day, but on the last day of our adventure at Yellowstone I made sure to share the Falls with her.