The Taughannock Falls Gorge Trail near Ithaca New York is an amazing flat 2 mile out-and-back hike to Taughannock Falls.
The waterfall is 215 feet tall. Well worth the visit, but this is a very popular trail. Dogs are allowed here, but there aren't many (if any) trails that lead off from the main trail.
Just before you reach the falls, you'll hike through a massive gorge with rock walls reaching hundreds of feet into the sky. It's an amazing short day hike if you're near Ithaca New York.