About

The Tres Hermanos Conservation Authority (Authority) is a joint powers agency with representatives from the cities of Chino Hills, Diamond Bar, and Industry. The purpose of the Authority is to coordinate the overall ownership, maintenance and use of the 2,445-acre Tres Hermanos Ranch property through the collaborative efforts of its Member Agencies.

Board Meetings

The Authority Board meetings are held the third Wednesday of the month at 6 p.m. in the Windmill Community Room at Diamond Bar City Hall, 21810 Copley Drive, Diamond Bar, CA 91765.  

Consistent with the Governor’s Executive Order, members of the public are encouraged to participate and address the Authority during the public comment portion of the meeting via teleconference.

Members of the Authority and limited staff may be physically present for this meeting.  If you would like to attend the meeting in person, please note that face coverings are required to be worn at all times.

For agendas and minutes, refer to the Tres Hermanos Conservation Authority meeting agenda calendar.

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