Lillian O'Grady's journal was a hunting journal.
Overview[]
Hunter Lillian O'Grady was hunting a Banshee and tracked it to the house of the Leahys. There, she found an infant Eileen Leahy and decided to train her to become a hunter. After sixteen years, Lillian died of cancer and her journal fell into Eileen's possession, who used it to hunt down the very Banshee that killed her parents.
After Eileen met Sam Winchester, she presented to him with this journal and explained her past with Lillian. The two used the knowledge gathered in the journal to hunt and kill the Banshee Eileen was after.
The journal's current whereabouts are unknown, especially after Eileen's death at the hands of a hellhound.