From the SMR at archaeology.ie, updated November, 2021:
Situated on a level landscape and just N of where three old field drains meet. A small circular feature described as ‘Lismahon Moat’ is depicted on the 1836 edition of the OS 6-inch map and it is described similarly on the 1908 edition. This is an oval, flat-topped and grass-covered mound (dims of base 16m E-W; 9m N-S; dims of top 6.5m E-W; 1.5m; H 1.6m at E to 2.2m at W) at the S corner of a field with large silted drains just to the E and W.