Warden of Westmarch
From Tolkien Gateway
Warden of Westmarch was a title granted by Thain Peregrin I, to Fastred of Greenholm in Fourth Age 35.
The title was hereditary, passed by Fastred to his son Elfstan Fairbairn, and associated from then on with the Fairbairns of the Towers. They held the heirloom of the Red Book.
It is unknown if the Warden was just a title, or also had any offices of responsibilities.