I do hope my dozen or so regular readers will pardon me if I write about someplace other than Covina just once. ;-)
Although I was born and raised in Covina, I lived my first five years on East Foothill Boulevard in Glendora, so consequently, the history of our neighbor to the north is a natural area of interest to me.
The subject is not far out of bounds geographically, either, as both Covina and Glendora share partial origins in a historical Mexican land grant called Rancho San José Adición (aka Rancho Addition to San Jose) which just happens to be the broader topic of this article. Most of Covina's Charter Oak neighborhood lies within Adición's borders, so I'm not really straying too far afield here.
Anyway, even as a child, I had a keen interest in roads, which really took off after I discovered my dad's Renie Atlas around age 12 (same time as my interest in Covina history, hmm!). Probably not long after that, the name of one street in particular from my Glendora years aroused my curiosity: "Compromise Line Road." Always wondered what that meant. Somewhere in my early readings of local history, I did learn that it involved a dispute over a northern boundary of Rancho Addition to San Jose, but I never could find out much more than that.

Compromise Line Road in Glendora. Source: Renie Atlas of Los Angeles City and County, 1965 edition.
Recently I was contacted by an old classmate who asked about Compromise Line, and desiring to know more than the basics I'd heard long ago, I decided to do a deep-dive into the subject. Obvious first stop reference-wise was Donald Pflueger's Glendora (1951), but unfortunately his mention of Compromise Line Road was so nonspecific as to be no help at all. Then I searched the newspaper archive, and that was a similar dead-end.



