Exactly who and when mountain was named, is not clear. By the early 1860s it was referred to Diamond Mountain. There are pockets of crystal quartz that can be found along the range, hence “diamond.”
In February 1910, Lassen County historian and retired school teacher, Asa M. Fairfield wanted to name the highest point on Diamond, Mount Roop. It went over like the proverbial “lead balloon.” Fairfield’s quest to have a feature named for Isaac Roop did not end. Fairfield consider Roop the father of Lassen County, while Peter Lassen received all the name recognition.
In 1921, Fairfield petitioned the United States Board of Geographical Names to rename Worley Mountain, to the west of Susanville. In 1922, the Board agreed and changed the name from Worley to Roop Mountain.
Personally, Susanville Peak would have been more fitting to the name designation. In Susanville’s historic core, one cannot see Roop/Worley Mountain. Yet, Susanville Peak is highly visible throughout the community. I still refer to Worley by its given name because when I was growing up that is what everyone referred to it as.