The Burren Mysteries by Cora Harrison got two member recommendations so far...
https://irelandxo.com/ireland-xo/visiting/books-burren-mystery-series
"I recommend My Lady Judge by Cora Harrison. One of a series about a female judge in medieval Ireland who uses the Brehon law to manage her villages. I was fascinated by the inclusion of a portion of Brehon law at the beginning of each chapter." ~ Kathleen
"I love The Burren Mysteries by Cora Harrison and Sister Fidelma series by Peter Tremayne. Both historical fiction set in a Pre- English time." ~ Julie