Tres Hermanos and the City of Industry

The view from the top of the Pantera Park trail provides a clear contrast. To the west, the hills of Diamond Bar are lightly peopled with roads and homes.

Looking to the east, cattle and horses graze on open land between the 60 freeway and Grand Avenue. Water towers to the south block a Diamond Bar housing development from view — far to the east, a small stretch of Chino Hills Parkway is visible.

Currently, the City of Industry owns this northern part of Tonner Canyon, which was acquired in the early 1980s, according to a timeline provided by the land-conservation non-profit Hills for Everyone, based in Brea.

Almost all of the stretch between the 60 freeway and Grand Avenue is within the city jurisdiction of Diamond Bar.

The land there was known as Tres Hermanos Ranch and any development of the land will be overseen by the Tres Hermanos Conservation Authority, which has the cities of Diamond Bar and Chino Hills as voting members, according to the blog The Carbon Canyon Chronicle.

This land is connected to the property on which currently stands. 

A Jan. 14 story in the Whittier Daily News said that Industry is now considering a further 500-acre aquisition in the southern portion of the Tonner Canyon property, though any details have not been discussed in open session.

A 2009 book by the Pulitzer Prize winning former Los Angeles Times reporter Victor Valle — with the domineering title, "City of Industry: Geneaologies of Power in Southern California," — focuses on corruption stemming from the City of Industry's founding, extending to the purchase of the Tres Hermanos land in the early 1980s.