The One Ring RPG: Horselords of Rohan
Horselords of Rohan - Rules of Play says:
Within this supplement are details of the ancient Forest of Fangorn, shedding light on its mysterious inhabitants, the Ents and terrible Huorns; the folk of the Dunland Fells; and the Tower of Isengard and the machinations of the White Wizard, Saruman.
It is also an indispensable resource for Loremasters looking to take their game into a whole new region. Ride with the Eorlingas on the plains of Westemnet, enter the Golden Hall of Edoras, and climb the Burg at Helm’s Deep.