The information on the Historic Environment Viewer says this rath is on high ground which 'presents an excellent view of the surrounding countryside', how lovely. Its story (which mixes various folklore themes) comes from the Schools Collection of the National Folklore Collection, written down in the 1930s, and currently being digitised at duchas.ie.
There is a fort in the townland of Ahanagran in the land of Thomas Fimertry. Every day there was a hare seen in this fort. This hare had only one ear.
One morning a number of men decided that they would kill the hare. They set off for the fort with a number of dogs. When they reached the fort, they saw the hare, but any one of the dogs would not touch him. Then the men followed the hare themselves, until they reached the bottom of the third field from the fort. All at once, a big hole opened in the ground and the hare went in.
The men followed the hare, but when they reached the bottom of the hole, to their surprise, instead of a hare being there they saw an old woman. They asked her if she saw any hare, but no sooner had they said it than the old woman disappeared. Then the men came up again, and the hole closed, but the hare was never again seen.